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SD Strange-results - or - How I learned to love CM7 on SD - Dec-11 results compiled!

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swoozle

Member
Feb 9, 2011
32
38
1/16/2012 update: Thanks to waxhell for compiling all of the results in this thread (at least as of mid-december! OK, so I took a while to get this posted...)
https://docs.google.com/spreadsheet/ccc?key=0AjPE3ZAD2eVudE9vZmQ3aHlfTkFvU2J4ZUplRDJQTEE

5/20 update: SD card performance benchmark table by a.fenderson from later in this thread added at the bottom of this post. Thank you a.fenderson!
------------------
April minor update with a Transcend SD (see http://forum.xda-developers.com/showpost.php?p=12964262&postcount=8)

_________________________________________________

Let me tell you my story.

Over the last couple of months as I have mucked around with SD booting various flavors of froyo and, more recently, CM7, I have found it maddening that there are apparently so many people that LOVE those versions, even people that seemed to have the same SD card as the two I've tried.

One of those is a Class 10 Patriot 8gig, which I've seen mentioned as an acceptable boot disk.
The other is a Kingston Class 4 4gig that tests out as significantly slower than the Patriot, but didn't really run froyo any slower.

Now I know I've seen posts that mention small block write speed as being important, but the numbers I've seen posted really didn't make me think the Patriot was the cause...
...the cause of FRUSTRATINGLY slow UI, where froyo (and CM7) seem to go off into lala-land for a few seconds every time I (tried to) do something.
...the cause of glacial web-surfing, where even downloading GOOGLEforchrissake takes forever. Of snail's-pace market downloads. Oh god.

Every time I would give up and go back to Eclair and breath a sigh of relief, reveling in the snappiness, the zippy web-surfing, the rapid response of m.pornhub.com.

And every time the siren song of the CM7-elite would call me back. THIS time I did something different. I saw mention that a Class 2, YES A FREAKING CLASS 2, Sandisk from costco worked well. So I skippity-skopped up and bought one.

After backing up the Patriot and writing THAT VERY SAME img to the Sandisk (which, yes, took 3 times as long as writing to the Patriot), I booted CM7.

OMG

The heavens opened and the angels sang, I HAD ARRIVED IN THE PROMISED LAND!
NOW I knew what the chosen had been praising! NOW I knew the joy that is CM7! ZIP-ZIP-ZIPPITY!

HOLY CRAP?! How could a benchmark be so misleading? I HATE those bastard SD manufacturers, or maybe it's the industry group that chose such a sucky measure of speed.

For your edification, here are some CrystalDiskMark (5 iterations, 50MB) results from 2 sucky cards and the good Sandisk.


__Test_________________Sandisk 8G Class 2___Patriot 8G Class 10____Kingston Class4 4Gig
Sequential Read :__________10.871 MB/s________20.036 MB/s___________18.700 MB/s
Sequential Write :__________6.659 MB/s________13.660 MB/s____________4.277 MB/s
Random Read 4KB (QD=32) :___3.077 MB/s_________3.444 MB/s____________2.088 MB/s
Random Write 4KB (QD=32) :__1.791 MB/s________0.038 MB/s_____________0.016 MB/s


Look at that, both the Kingston and the Patriot blow away or are close enough to the Sandisk in everything BUT....

(wait for it)....

SMALL BLOCK RANDOM WRITES
where the Sandisk is FIFTY times the speed of the Patriot and ONE HUNDREDtimes the Kingston.

Now you may say, "Swizzlenuts, old pal, I KNEW that."

But for all you poor slobs who didn't, who are dragging yer sorry ass through the broken glass that is booting off of a slow SD (you know who both of you are), I hope this helps.

And now you may commence posting links to specific posts where this info was discussed in detail last December.


------------------
Thanks to all of the people that posted their results and to a.fenderson for compiling them. Here's his table from http://forum.xda-developers.com/showpost.php?p=13991898&postcount=144
Code:
POSTER         BRAND      CLASS  CAPACITY  4 KB RANDOM
                                  (GB)    WRITE QD32(MB/s)    NOTE
swoozle        SanDisk        2    8          1.791           Model: SDSQ-8192-AC11M
a.fenderson    SanDisk        4    16         1.660           SanDisk C4 16GB 1 of 2 cards
MickMcGeough   SanDisk        4    8          1.59            benchmarked in XBench, QD unknown
a.fenderson    SanDisk        4    16         1.500           SanDisk C4 16GB 2 of 2 cards
Awats          SanDisk        4    16         1.391           SanDisk C4 16GB 1 of 2 cards ; fastest (onboard) reader
arwild01       SanDisk        4    8          1.369    
Awats          SanDisk        4    16         1.284           SanDisk C4 16GB 2 of 2 cards ; fastest (onboard) reader
robot8         SanDisk        4    8          1.270           SanDisk C4 8GB 2 of 2 cards
robot8         SanDisk        4    8          1.259           SanDisk C4 8GB 1 of 2 cards
chinly43       SanDisk        4    16         1.257           (not via Nook) ; same card as chinly43's other listed SanDisk C4 16GB
joobu          SanDisk        4    4          1.175    
angomy         Nook internal  N/A N/A         1.116           via Nook on USB
chinly43       Nook internal  N/A N/A         1.094           via Nook on USB
a.fenderson    Transcend      2    32         1.032    
a.fenderson    SanDisk        4    4          0.898    
a.fenderson    SanDisk        2    4          0.891    
pchoi94        SanDisk        4    16         0.834    
chinly43       SanDisk        4    16         0.769           via Nook on USB ; same as chinly43's other listed SanDisk C4 16GB
pryonix        SanDisk        4    8          0.625    
chinly43       SanDisk        2    8          0.616    
a.fenderson    SanDisk        4    8          0.596    
angomy         SanDisk        4    16         0.574    
Blue6IX        SanDisk        2    16         0.350    
a.fenderson    SanDisk       N/A   2          0.269    
Awats          SanDisk        4    2          0.261           SanDisk C4 2GB 1 of 2 cards ; fastest (onboard) reader
Awats          SanDisk        4    2          0.236           SanDisk C4 2GB 2 of 2 cards ; fastest (onboard) reader
pryonix        Samsung       N/a   2          0.093    
victle         Kingston      N/A   2          0.051    
victle         Dane-Elec     N/A   2          0.050           0.050 or less:  exact value unspecified
joobu          Lexar          4    8          0.038    
swoozle        Patriot        10   8          0.038    
Blue6IX        Dane-Elec      4    4          0.037           (made in Japan)
omghahalol     Transcend      6    16         0.037    
Ravynmagi      Samsung(??)    2    4          0.037    
pryonix        Kingmax        10   16         0.036    
Ravynmagi      Wintech        10   16         0.036    
victle         Transcend      6    4          0.034    
omghahalol     Transcend      6    8          0.033    
Ravynmagi      SanDisk        2    8          0.033    
pryonix        Transcend      6    8          0.033    
Ravynmagi      Patriot        10   16         0.030    
Blue6IX        PNY            10   8          0.030    
pchoi94        Kingston       2    16         0.030    
swoozle        Transcend      6    8          0.029           Model: TS8GUSDHC6
joobu          ??            N/A   2          0.029    
chinly43       SanDisk       N/A   1          0.029    
a.fenderson    SanDisk       N/A   1          0.028    
victle         PNY            4    8          0.028    
Blue6IX        PNY           N/A   2          0.027           (made in Taiwan)
omghahalol     SanDisk        2    2          0.021    
MickMcGeough   SanDisk        2    8          0.02           benchmarked in XBench, QD unknown
robot8         Transcend      6    8          0.018           Transcend C6 8GB 1 of 2 cards
ExploreMN      Patriot        10   16         0.018    
arwild01       Samsung(??)    4    8          0.017    
swoozle        Kingston       4    4          0.016           Model: SDC4/8GB
Awats          Patriot        4    4          0.016           Patriot C4 4GB 1 of 2 cards ; fastest (onboard) reader
robot8         Transcend      6    8          0.014           Transcend C6 8GB 2 of 2 cards
Tnexus         Patriot        10   16         0.014    
a.fenderson    Kingston       4    8          0.014    
Awats          Patriot        4    4          0.011           Patriot C4 4GB 2 of 2 cards ; fastest (onboard) reader
chinly43       Lexar          4    8          0.011
 
Last edited:

xdabr

Senior Member
Mar 14, 2011
141
7
Both entertaining and edifying.

Thanks, swoozle! (I mean "swizzlenuts" old pal?)

Now if only that obscure performance metric were easily determined from printed SD card specifications...
 

victle

Senior Member
Jun 20, 2010
84
9
Yeah, I have two old 2G uSD (no classified) and both work fine with CM7. The benchmarks are almost as good as the well tested Transcend 4GB class 6, random write speed beat the Transcend, but random read is little bit slower :)
 
Last edited:

ax135

Member
Mar 13, 2011
20
3
I experienced the same thing

All my so call fast cards (class 6 and class 10) worked very slow or had boot problems. After switching the to the Costco Sandisk class 4 card, I was able to use CM7, HD, and all the other images with good preformance from the SD card.

Let me tell you my story.

Over the last couple of months as I have mucked around with SD booting various flavors of froyo and, more recently, CM7, I have found it maddening that there are apparently so many people that LOVE those versions, even people that seemed to have the same SD card as the two I've tried.

One of those is a Class 10 Patriot 8gig, which I've seen mentioned as an acceptable boot disk.
The other is a Kingston Class 4 4gig that tests out as significantly slower than the Patriot, but didn't really run froyo any slower.

Now I know I've seen posts that mention small block write speed as being important, but the numbers I've seen posted really didn't make me think the Patriot was the cause...
...the cause of FRUSTRATINGLY slow UI, where froyo (and CM7) seem to go off into lala-land for a few seconds every time I (tried to) do something.
...the cause of glacial web-surfing, where even downloading GOOGLEforchrissake takes forever. Of snail's-pace market downloads. Oh god.

Every time I would give up and go back to Eclair and breath a sigh of relief, reveling in the snappiness, the zippy web-surfing, the rapid response of m.pornhub.com.

And every time the siren song of the CM7-elite would call me back. THIS time I did something different. I saw mention that a Class 2, YES A FREAKING CLASS 2, Sandisk from costco worked well. So I skippity-skopped up and bought one.

After backing up the Patriot and writing THAT VERY SAME img to the Sandisk (which, yes, took 3 times as long as writing to the Patriot), I booted CM7.

O
M
G


The heavens opened and the angels sang, I HAD ARRIVED IN THE PROMISED LAND!
NOW I knew what the chosen had been praising! NOW I knew the joy that is CM7! ZIP-ZIP-ZIPPITY!

HOLY CRAP?! How could a benchmark be so misleading? I HATE those bastard SD manufacturers, or maybe it's the industry group that chose such a sucky measure of speed.

For your edification, here are some CrystalDiskMark results from 2 sucky cards and the good Sandisk.


__Test_________________Sandisk 8G Class 2___Patriot 8G Class 10____Kingston Class4 4Gig
Sequential Read :__________10.871 MB/s________20.036 MB/s___________18.700 MB/s
Sequential Write :__________6.659 MB/s________13.660 MB/s____________4.277 MB/s
Random Read 4KB (QD=32) :___3.077 MB/s_________3.444 MB/s____________2.088 MB/s
Random Write 4KB (QD=32) :__1.791 MB/s________0.038 MB/s_____________0.016 MB/s


Look at that, both the Kingston and the Patriot blow away or are close enough to the Sandisk in everything BUT....

(wait for it)....


SMALL BLOCK RANDOM WRITES
where the Sandisk is FIVE times the speed of the Patriot and TEN times the Kingston.

Now you may say, "Swizzlenuts, old pal, I KNEW that."

But for all you poor slobs who didn't, who are dragging yer sorry ass through the broken glass that is booting off of a slow SD (you know who both of you are), I hope this helps.

And now you may commence posting links to specific posts where this info was discussed in detail last December.

:)
 
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patgnds

Senior Member
Jan 16, 2011
54
4
I have a Transcend 8gb class 6 and Kinkmax 8gb class 6 none work well. The Transcend is by far the better of the two. I have now ordered a 16GB Sandisk class 2 to see how that works.
 

swoozle

Member
Feb 9, 2011
32
38
Update:Transcend

Just a minor addition with a Transcend card. I'd seen many posts that swore by a Transcend Cl 6 8G card through Newegg. I ordered, received, benchmarked and loaded CM7 Nightly 37.
To cut to the chase, the Transcend sucked big hairy monkey balls. Similar small block write speeds as the other crappy cards. And the CM7 performance was predictably bad. Crappy UI response and FCs.

__Test_________Sandisk Cl2 8G___Patriot CL10 8G____Kingston Cl4 4Gig___Transcend Cl6 8G
Sequential Read___10.871 MB/s____20.036 MB/s___________18.700 MB/s___________19.930 MB/s
Sequential Write___6.659 MB/s____13.660 MB/s____________4.277 MB/s___________19.325 MB/s
Rndm Rd 4KB(QD32)__3.077 MB/s_____3.444 MB/s____________2.088 MB/s___________2.968 MB/s
Rndm Wrt 4KB(QD32)_1.791 MB/s_____0.038 MB/s____________0.016 MB/s___________0.029 MB/s

I'm sure any of these would work fine as data cards. But for running off of SD, it makes a huge difference.
 

tyy10002

Senior Member
Dec 11, 2010
198
19
+1.

My PNY card was too slow and it took forever to download apps from market (CM7) and I replaced it with a old 8G class 2 sandisk.. Man.. no need to say it..

BTW, anyone why does sandisk makes class 6 or class 10 micro SD card? I did find the extreme III of SD card only... and not the micro card.
 

robot8

Senior Member
Apr 4, 2011
111
20
Just a minor addition with a Transcend card. I'd seen many posts that swore by a Transcend Cl 6 8G card through Newegg. I ordered, received, benchmarked and loaded CM7 Nightly 37.
To cut to the chase, the Transcend sucked big hairy monkey balls. Similar small block write speeds as the other crappy cards. And the CM7 performance was predictably bad. Crappy UI response and FCs.

...

I'm sure any of these would work fine as data cards. But for running off of SD, it makes a huge difference.

I have been running off a Transcend CL6 8G card and while my install felt zippy and pretty smooth, I have been having some FC issues and random quirkiness. I believe you have smacked the nail on the head here in that what really matters is the speed of the small block random writes. Having ruled out all other possibilities, it is the only thing that may explain why I am having intermittent artifacts in my streaming video.

Thank you for posting your tests and results, gonna go grab an el cheapo Cl2 card asap.

edit: So I picked up a cheap Class 2 Sandisk 8G card and it's been rock solid on the latest nightly 41 with 4.18C test kernel.
 
Last edited:

residentorca

Senior Member
Jan 24, 2011
270
72
Seattle
Moto G Play
From my experience using CM7 on different high-speed uSD cards (Kingston, Patriot and Transcend), the results between brands and within brands are inconclusive and inconsistent. I'm beginning to think it has more to do with the individual card, i.e., the luck of the draw (or lack thereof). With such hit-or-miss results, perhaps the best approach is to keep trying until you find a good one.
 
Jun 18, 2010
37
0
Kansas City, MO
I'm having a similar oddity... I have CM7 installed to eMMC, and on an 8GB Class 4 SanDisk MicroSD. The microSD actually boots /faster/, and has less UI lag than the internal memory!

Wondering if I messed up the flash (redid it a few times with no real change), install process, or if the internal memory is actually slower than the microSD somehow. Kind of backward thinking to my mind, but hey...
 

joobu

Member
Mar 10, 2011
17
2
I think SD card variability isn't sufficiently highlighted in instructions for running off the SD card. I had issues with a Transcend class 6 4 GB card but no issues with an unclassified 2 GB.

If this issue is highlighted I think it might avoid a lot of frustration.
 

joobu

Member
Mar 10, 2011
17
2
I'm seeing similar results with my cards on Random Write 4KB(QD32):
Sandisk Class 4 4GB:_________1.175 MB/s
Random unclassified 2GB:_____0.029 MB/s
Lexar Class 4 8GB:___________0.038 MB/s
 
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twobits

Member
Apr 28, 2011
5
1

__Test_________________Sandisk 8G Class 2___Patriot 8G Class 10____Kingston Class4 4Gig
Sequential Read :__________10.871 MB/s________20.036 MB/s___________18.700 MB/s
Sequential Write :__________6.659 MB/s________13.660 MB/s____________4.277 MB/s
Random Read 4KB (QD=32) :___3.077 MB/s_________3.444 MB/s____________2.088 MB/s
Random Write 4KB (QD=32) :__1.791 MB/s________0.038 MB/s_____________0.016 MB/s


Look at that, both the Kingston and the Patriot blow away or are close enough to the Sandisk in everything BUT....

(wait for it)....


SMALL BLOCK RANDOM WRITES
where the Sandisk is FIVE times the speed of the Patriot and TEN times the Kingston.

I have only ever seen the sequential speeds quoted in specs. In fact, if the SanDisk was only 10x faster then the Kingston would need to be .16 and not .016 right? So isn't the sandisk actually 50x and 100x faster?

How can we find card with decent random r/w performance though, does anyone spec for that?
 
Last edited:

swoozle

Member
Feb 9, 2011
32
38
Woops, you are correct. Missed a zero, thanks.
:p

No, I've never seen such a spec quoted either. I imagine it's because any normal use of an SD card doesn't depend on random write speed so much.
 

BrotherZero

Senior Member
Mar 22, 2011
188
26
Hm, here I had given up running anything from an SD since I failed to even boot up either Froyo or CM7 with mine. But I have a 16gb Sandisk class 2 in my other phone! Going to try that then.
Noobquestion, how do you back up an android SD-card? Can I just copy paste the entire card to my pc hard drive, and then transfer it back when I want to use it in my phone again? Or do I have to use some kind of backup program?
 

micksh

Member
Oct 7, 2006
35
5
The results are not strange. Card class only reflects sequential speed, but random speed is more important for OS operation. For example, ReadyBoost certified Flash drives have to have certain minimum random access speed.
Similar issue was brought up when people tried to replace SD cards in WP7 phones:

the big issue is random access performance -- a figure that isn't taken into account in a card's class rating. Ironically, Microsoft discovered in its testing that cards with higher class ratings actually performed worse on Windows Phone 7 because the tweaks card manufacturers make to achieve high sequential throughput can actually hurt random access times.
http://www.engadget.com/2010/11/17/windows-phone-7s-microsd-mess-the-full-story-and-how-nokia-ca/

It's good to know that Sandisk cards generally have good random access speed. However, it's not guarantied. They may choose cheaper NAND any time in future.

Added: For guarantied result one may try to find ReadyBoost certified microSD, but I don't know if they exist, probably they certified only USB sticks.
Or, WP7-certified microSD cards just recently started to appear.
http://www.engadget.com/2011/04/15/windows-phone-7-certified-microsd-cards-emerge-at-atandt-stores/
Right now it's probably the same Sandisk card, just repackaged and priced higher. If I were to buy microSD to run OS from I would choose Sandisk and would hope that I'm lucky.
But WP7-certified cards could be a good choice if regular Sandisk cards suddenly become worse or if you just want to be sure, they should have good random access speed.
 
Last edited:

ebubar

Member
Apr 18, 2011
28
2
This is surprising to read. I've looked pretty much everywhere and the consensus has seemed to be that the Transcend 8GB, class 6 cards were top notch. Just ordered one off of Amazon too:(. Maybe I should just grab a Sandisk instead.
 

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  • 34
    1/16/2012 update: Thanks to waxhell for compiling all of the results in this thread (at least as of mid-december! OK, so I took a while to get this posted...)
    https://docs.google.com/spreadsheet/ccc?key=0AjPE3ZAD2eVudE9vZmQ3aHlfTkFvU2J4ZUplRDJQTEE

    5/20 update: SD card performance benchmark table by a.fenderson from later in this thread added at the bottom of this post. Thank you a.fenderson!
    ------------------
    April minor update with a Transcend SD (see http://forum.xda-developers.com/showpost.php?p=12964262&postcount=8)

    _________________________________________________

    Let me tell you my story.

    Over the last couple of months as I have mucked around with SD booting various flavors of froyo and, more recently, CM7, I have found it maddening that there are apparently so many people that LOVE those versions, even people that seemed to have the same SD card as the two I've tried.

    One of those is a Class 10 Patriot 8gig, which I've seen mentioned as an acceptable boot disk.
    The other is a Kingston Class 4 4gig that tests out as significantly slower than the Patriot, but didn't really run froyo any slower.

    Now I know I've seen posts that mention small block write speed as being important, but the numbers I've seen posted really didn't make me think the Patriot was the cause...
    ...the cause of FRUSTRATINGLY slow UI, where froyo (and CM7) seem to go off into lala-land for a few seconds every time I (tried to) do something.
    ...the cause of glacial web-surfing, where even downloading GOOGLEforchrissake takes forever. Of snail's-pace market downloads. Oh god.

    Every time I would give up and go back to Eclair and breath a sigh of relief, reveling in the snappiness, the zippy web-surfing, the rapid response of m.pornhub.com.

    And every time the siren song of the CM7-elite would call me back. THIS time I did something different. I saw mention that a Class 2, YES A FREAKING CLASS 2, Sandisk from costco worked well. So I skippity-skopped up and bought one.

    After backing up the Patriot and writing THAT VERY SAME img to the Sandisk (which, yes, took 3 times as long as writing to the Patriot), I booted CM7.

    OMG

    The heavens opened and the angels sang, I HAD ARRIVED IN THE PROMISED LAND!
    NOW I knew what the chosen had been praising! NOW I knew the joy that is CM7! ZIP-ZIP-ZIPPITY!

    HOLY CRAP?! How could a benchmark be so misleading? I HATE those bastard SD manufacturers, or maybe it's the industry group that chose such a sucky measure of speed.

    For your edification, here are some CrystalDiskMark (5 iterations, 50MB) results from 2 sucky cards and the good Sandisk.


    __Test_________________Sandisk 8G Class 2___Patriot 8G Class 10____Kingston Class4 4Gig
    Sequential Read :__________10.871 MB/s________20.036 MB/s___________18.700 MB/s
    Sequential Write :__________6.659 MB/s________13.660 MB/s____________4.277 MB/s
    Random Read 4KB (QD=32) :___3.077 MB/s_________3.444 MB/s____________2.088 MB/s
    Random Write 4KB (QD=32) :__1.791 MB/s________0.038 MB/s_____________0.016 MB/s


    Look at that, both the Kingston and the Patriot blow away or are close enough to the Sandisk in everything BUT....

    (wait for it)....

    SMALL BLOCK RANDOM WRITES
    where the Sandisk is FIFTY times the speed of the Patriot and ONE HUNDREDtimes the Kingston.

    Now you may say, "Swizzlenuts, old pal, I KNEW that."

    But for all you poor slobs who didn't, who are dragging yer sorry ass through the broken glass that is booting off of a slow SD (you know who both of you are), I hope this helps.

    And now you may commence posting links to specific posts where this info was discussed in detail last December.


    ------------------
    Thanks to all of the people that posted their results and to a.fenderson for compiling them. Here's his table from http://forum.xda-developers.com/showpost.php?p=13991898&postcount=144
    Code:
    POSTER         BRAND      CLASS  CAPACITY  4 KB RANDOM
                                      (GB)    WRITE QD32(MB/s)    NOTE
    swoozle        SanDisk        2    8          1.791           Model: SDSQ-8192-AC11M
    a.fenderson    SanDisk        4    16         1.660           SanDisk C4 16GB 1 of 2 cards
    MickMcGeough   SanDisk        4    8          1.59            benchmarked in XBench, QD unknown
    a.fenderson    SanDisk        4    16         1.500           SanDisk C4 16GB 2 of 2 cards
    Awats          SanDisk        4    16         1.391           SanDisk C4 16GB 1 of 2 cards ; fastest (onboard) reader
    arwild01       SanDisk        4    8          1.369    
    Awats          SanDisk        4    16         1.284           SanDisk C4 16GB 2 of 2 cards ; fastest (onboard) reader
    robot8         SanDisk        4    8          1.270           SanDisk C4 8GB 2 of 2 cards
    robot8         SanDisk        4    8          1.259           SanDisk C4 8GB 1 of 2 cards
    chinly43       SanDisk        4    16         1.257           (not via Nook) ; same card as chinly43's other listed SanDisk C4 16GB
    joobu          SanDisk        4    4          1.175    
    angomy         Nook internal  N/A N/A         1.116           via Nook on USB
    chinly43       Nook internal  N/A N/A         1.094           via Nook on USB
    a.fenderson    Transcend      2    32         1.032    
    a.fenderson    SanDisk        4    4          0.898    
    a.fenderson    SanDisk        2    4          0.891    
    pchoi94        SanDisk        4    16         0.834    
    chinly43       SanDisk        4    16         0.769           via Nook on USB ; same as chinly43's other listed SanDisk C4 16GB
    pryonix        SanDisk        4    8          0.625    
    chinly43       SanDisk        2    8          0.616    
    a.fenderson    SanDisk        4    8          0.596    
    angomy         SanDisk        4    16         0.574    
    Blue6IX        SanDisk        2    16         0.350    
    a.fenderson    SanDisk       N/A   2          0.269    
    Awats          SanDisk        4    2          0.261           SanDisk C4 2GB 1 of 2 cards ; fastest (onboard) reader
    Awats          SanDisk        4    2          0.236           SanDisk C4 2GB 2 of 2 cards ; fastest (onboard) reader
    pryonix        Samsung       N/a   2          0.093    
    victle         Kingston      N/A   2          0.051    
    victle         Dane-Elec     N/A   2          0.050           0.050 or less:  exact value unspecified
    joobu          Lexar          4    8          0.038    
    swoozle        Patriot        10   8          0.038    
    Blue6IX        Dane-Elec      4    4          0.037           (made in Japan)
    omghahalol     Transcend      6    16         0.037    
    Ravynmagi      Samsung(??)    2    4          0.037    
    pryonix        Kingmax        10   16         0.036    
    Ravynmagi      Wintech        10   16         0.036    
    victle         Transcend      6    4          0.034    
    omghahalol     Transcend      6    8          0.033    
    Ravynmagi      SanDisk        2    8          0.033    
    pryonix        Transcend      6    8          0.033    
    Ravynmagi      Patriot        10   16         0.030    
    Blue6IX        PNY            10   8          0.030    
    pchoi94        Kingston       2    16         0.030    
    swoozle        Transcend      6    8          0.029           Model: TS8GUSDHC6
    joobu          ??            N/A   2          0.029    
    chinly43       SanDisk       N/A   1          0.029    
    a.fenderson    SanDisk       N/A   1          0.028    
    victle         PNY            4    8          0.028    
    Blue6IX        PNY           N/A   2          0.027           (made in Taiwan)
    omghahalol     SanDisk        2    2          0.021    
    MickMcGeough   SanDisk        2    8          0.02           benchmarked in XBench, QD unknown
    robot8         Transcend      6    8          0.018           Transcend C6 8GB 1 of 2 cards
    ExploreMN      Patriot        10   16         0.018    
    arwild01       Samsung(??)    4    8          0.017    
    swoozle        Kingston       4    4          0.016           Model: SDC4/8GB
    Awats          Patriot        4    4          0.016           Patriot C4 4GB 1 of 2 cards ; fastest (onboard) reader
    robot8         Transcend      6    8          0.014           Transcend C6 8GB 2 of 2 cards
    Tnexus         Patriot        10   16         0.014    
    a.fenderson    Kingston       4    8          0.014    
    Awats          Patriot        4    4          0.011           Patriot C4 4GB 2 of 2 cards ; fastest (onboard) reader
    chinly43       Lexar          4    8          0.011
    6
    This thread should be pinned: specifically the list of cards and their bench results. I was amazed at what a difference changing my SD card made.

    I fear swoozle (the OP) may have abandoned us, but if not or if an admin who wants to sticky this thread could do so, I'd be glad for someone to copy and paste the list I keep updating to the end of the first post. Speaking of that:

    Code:
    POSTER		BRAND		CLASS	CAPACITY (GB)	4 KB RANDOM WRITE QD32 (MB/s)	NOTE
    swoozle		SanDisk		2	8		1.791	
    a.fenderson	SanDisk		4	16		1.660				SanDisk C4 16GB 1 of 2 cards
    MickMcGeough	SanDisk		4	8		1.59				benchmarked in XBench, QD unknown
    a.fenderson	SanDisk		4	16		1.500				SanDisk C4 16GB 2 of 2 cards
    Awats		SanDisk		4	16		1.391				SanDisk C4 16GB 1 of 2 cards ; fastest (onboard) reader
    arwild01	SanDisk		4	8		1.369	
    Awats		SanDisk		4	16		1.284				SanDisk C4 16GB 2 of 2 cards ; fastest (onboard) reader
    robot8		SanDisk		4	8		1.270				SanDisk C4 8GB 2 of 2 cards
    robot8		SanDisk		4	8		1.259				SanDisk C4 8GB 1 of 2 cards
    chinly43	SanDisk		4	16		1.257				(not via Nook) ; same card as chinly43's other listed SanDisk C4 16GB
    joobu		SanDisk		4	4		1.175	
    angomy		Nook internal	N/A	N/A		1.116				via Nook on USB
    chinly43	Nook internal	N/A	N/A		1.094				via Nook on USB
    a.fenderson	Transcend	2	32		1.032		
    a.fenderson	SanDisk		4	4		0.898	
    a.fenderson	SanDisk		2	4		0.891	
    pchoi94		SanDisk		4	16		0.834	
    chinly43	SanDisk		4	16		0.769				via Nook on USB ; same as chinly43's other listed SanDisk C4 16GB
    pryonix		SanDisk		4	8		0.625	
    chinly43	SanDisk		2	8		0.616	
    a.fenderson	SanDisk		4	8		0.596	
    angomy		SanDisk		4	16		0.574	
    Blue6IX		SanDisk		2	16		0.350	
    a.fenderson	SanDisk		N/A	2		0.269	
    Awats		SanDisk		4	2		0.261				SanDisk C4 2GB 1 of 2 cards ; fastest (onboard) reader
    Awats		SanDisk		4	2		0.236				SanDisk C4 2GB 2 of 2 cards ; fastest (onboard) reader
    pryonix		Samsung		N/a	2		0.093	
    victle		Kingston	N/A	2		0.051	
    victle		Dane-Elec	N/A	2		0.050				0.050 or less:  exact value unspecified
    joobu		Lexar		4	8		0.038	
    swoozle		Patriot		10	8		0.038	
    Blue6IX		Dane-Elec	4	4		0.037				(made in Japan)
    omghahalol 	Transcend	6	16		0.037	
    Ravynmagi	Samsung(??)	2	4		0.037	
    pryonix		Kingmax		10	16		0.036	
    Ravynmagi	Wintech		10	16		0.036	
    victle		Transcend	6	4		0.034	
    omghahalol 	Transcend	6	8		0.033	
    Ravynmagi	SanDisk		2	8		0.033	
    pryonix		Transcend	6	8		0.033	
    Ravynmagi	Patriot		10	16		0.030	
    Blue6IX		PNY		10	8		0.030	
    pchoi94		Kingston	2	16		0.030	
    swoozle		Transcend	6	8		0.029	
    joobu		??		N/A	2		0.029	
    chinly43	SanDisk		N/A	1		0.029	
    a.fenderson	SanDisk		N/A	1		0.028	
    victle		PNY		4	8		0.028	
    Blue6IX		PNY		N/A	2		0.027				(made in Taiwan)
    omghahalol 	SanDisk		2	2		0.021	
    MickMcGeough	SanDisk		2	8		0.02				benchmarked in XBench, QD unknown
    robot8		Transcend	6	8		0.018				Transcend C6 8GB 1 of 2 cards
    ExploreMN	Patriot		10	16		0.018	
    arwild01	Samsung(??)	4	8		0.017	
    swoozle		Kingston	4	4		0.016	
    Awats		Patriot		4	4		0.016				Patriot C4 4GB 1 of 2 cards ; fastest (onboard) reader
    robot8		Transcend	6	8		0.014				Transcend C6 8GB 2 of 2 cards
    Tnexus		Patriot		10	16		0.014	
    a.fenderson	Kingston	4	8		0.014	
    Awats		Patriot		4	4		0.011				Patriot C4 4GB 2 of 2 cards ; fastest (onboard) reader
    chinly43	Lexar		4	8		0.011
    4
    Hi,

    I'm getting my nook next week, and I'm trying to pick an SD for it. I initially wanted an 8GB Class 6 Adata, but they're quite difficult to get a hold of in the UK.

    I'm torn between a SanDisk Class 4 and a Samsung Class 6. Both are 8GB.

    Anyone got any experience with Samsung or should I still to the tried and tested SanDisk?

    edit: I managed to find somewhere with a Class 6 Adata, so that's still an option.

    Any advice would be much appreciated.

    Will you be running your Android install off the SD card, or just using it for data?
    If just data, you'll be fine for most applications.

    I benchmarked several brand-new SanDisk cards of varying capacities, and all the >= 4 GB cards were Class 4, but even so it was hit-or-miss: random 4K writes for the 1 and 2 GB cards sucked, the 4 GB card was decent, the 8 GB card was half as fast as the 4 GB, one of the 16 GB cards looked great, and the other had kind of inconsistent results. So even within the same brand (and class rating where applicable), there is a lot of variation, unfortunately. You might look below and narrow your purchasing options down to those combinations of brand, size, and Class whose 4K random writes are shown to be around 1.00 MB/s or better, though really there are two orders of magnitude difference between the truly crappy cards and the best ones, so even cards with 0.1 to 0.9 MB/s 4K random writes might suffice when compared to the 0.0X cards. In general, so far it looks like SanDisk Class 4 and 2 vary between good (~.5 MB/s) and excellent (~1.5 MB/s), though unclassed SanDisk aren't so great.

    If running CM7 (etc) off it, my best advice is to test whatever card(s) you do end up buying with CrystalDiskMark and only using it as your boot disk if the 4K random writes are approximately equal to or greater than 1.00 MB/s.

    @all: the anecdotal reports of your cards running well are great, but if you have the time, please benchmark your cards with CrystalDiskMark so that we can all get enough data to be more confident in our card purchases. If you're worried about AV warnings when you download, please see this post where I explained what the opencandy component of the installer does and does not do (it's not malware). Also, along with your benchmarks, please provide your evaluation of how well the card runs your ROM, etc, if applicable.

    Here's a compilation of the actual benchmarking data thus far in this thread (with the only benchmakred data presented as 4 KB random write w/ QD=32, since this is the only commonality among all posters). It's been sorted (descending) on the write speed column:

    Code:
    POSTER		BRAND		CLASS	CAPACITY (GB)	4 KB RANDOM WRITE QD32 (MB/s)
    swoozle		SanDisk		2	8		1.791
    a.fenderson	SanDisk		4	16		1.660
    a.fenderson	SanDisk		4	16		1.500
    robot8		SanDisk		4	8		1.259
    chinly43	SanDisk		4	16		1.257
    joobu		SanDisk		4	4		1.175
    angomy		Nook internal	N/A	N/A		1.116
    a.fenderson	Transcend	2	32		1.032
    a.fenderson	SanDisk		4	4		0.898
    chinly43	SanDisk		2	8		0.616
    a.fenderson	SanDisk		4	8		0.596
    angomy		SanDisk		4	16		0.574
    a.fenderson	SanDisk		N/A	2		0.269
    swoozle		Patroit		10	8		0.038
    joobu		Lexar		4	8		0.038
    swoozle		Transcend	6	8		0.029
    joobu		??		N/A	2		0.029
    chinly43	SanDisk		N/A	1		0.029
    a.fenderson	SanDisk		N/A	1		0.028
    robot8		Transcend	6	8		0.018
    ExploreMN	Patroit		10	16		0.018
    swoozle		Kingston	4	4		0.016
    Tnexus		Patroit		10	16		0.014
    a.fenderson	Kingston	4	8		0.014
    chinly43	Lexar		4	8		0.011
    2
    Thanks a lot for clarifying, I will try it out now that I know I can opt out of the install.

    Edit: Ran CrystalDiskMark for 16GB class 4 Sandisk card vs internal nook storage via USB storage mode:

    Sandisk 16GB class 4 (non-Ultra+)

    Sequential Read : 20.003 MB/s
    Sequential Write : 3.086 MB/s
    Random Read 512KB : 20.113 MB/s
    Random Write 512KB : 1.372 MB/s
    Random Read 4KB (QD=1) : 5.143 MB/s [ 1255.7 IOPS]
    Random Write 4KB (QD=1) : 0.594 MB/s [ 145.1 IOPS]
    Random Read 4KB (QD=32) : 6.019 MB/s [ 1469.4 IOPS]
    Random Write 4KB (QD=32) : 0.574 MB/s [ 140.1 IOPS]


    Nook internal:

    Sequential Read : 19.970 MB/s
    Sequential Write : 3.937 MB/s
    Random Read 512KB : 20.634 MB/s
    Random Write 512KB : 2.173 MB/s
    Random Read 4KB (QD=1) : 4.905 MB/s [ 1197.5 IOPS]
    Random Write 4KB (QD=1) : 1.106 MB/s [ 270.0 IOPS]
    Random Read 4KB (QD=32) : 4.446 MB/s [ 1085.4 IOPS]
    Random Write 4KB (QD=32) : 1.116 MB/s [ 272.4 IOPS]
    2
    Update:Transcend

    Just a minor addition with a Transcend card. I'd seen many posts that swore by a Transcend Cl 6 8G card through Newegg. I ordered, received, benchmarked and loaded CM7 Nightly 37.
    To cut to the chase, the Transcend sucked big hairy monkey balls. Similar small block write speeds as the other crappy cards. And the CM7 performance was predictably bad. Crappy UI response and FCs.

    __Test_________Sandisk Cl2 8G___Patriot CL10 8G____Kingston Cl4 4Gig___Transcend Cl6 8G
    Sequential Read___10.871 MB/s____20.036 MB/s___________18.700 MB/s___________19.930 MB/s
    Sequential Write___6.659 MB/s____13.660 MB/s____________4.277 MB/s___________19.325 MB/s
    Rndm Rd 4KB(QD32)__3.077 MB/s_____3.444 MB/s____________2.088 MB/s___________2.968 MB/s
    Rndm Wrt 4KB(QD32)_1.791 MB/s_____0.038 MB/s____________0.016 MB/s___________0.029 MB/s

    I'm sure any of these would work fine as data cards. But for running off of SD, it makes a huge difference.