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SD821 Underclocked in pixel devices

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ramqashou

Senior Member
Mar 25, 2015
156
48
The pixel XI and the pixel are packed with snadragon 821 chipset wich supposed to be clocked at 2*2.35 kryo & 2*2.0 kryo but both pixel phones are clocked at 2*2.15 kryo & 2*1.6 Kryo which is exactly the same as SD820 on Lg G5 and the s7 so if someone knows what is the difference between the cpu in the pixel phones and the regular snapdragon 820 please write it down
 

hockeyman12c

Senior Member
Sep 15, 2007
175
46
From what I have read the 821 is a 820. The 821 is just higher binned 820. When they make chips they are not all the same. Some just are a little more efficient than others do to very minor differences in the chips. So a high binned 820 can handle a higher clock speed while using less power are turned into 821.

So Google decided they wanted to go with the 821 because it is more power efficient than a 820. But it seems Google thinks the speed of the 820 is fast enough to provide a good snappy user experience. So they are doubling down on efficiency by clocking these high binned chips down to the same as the 820. So say the 821 is 5% more efficient at stock speed over the 820. The 821 might be 10% more efficient at the same clock speed at the 820 while delivering the same speed as the 820. So they are sort of doubling down on efficiency over performance.

From the hands on I have seen everyone has described the phone as very fast. This is likely due to Google optimizing Android to run on the pixels hardware. Much like Apple does with the iPhone. Also the Pixel has some hardware features that might not show up on a regular spec sheet. It has some improved touch screen latency and faster storage. Because of these factors Google decided they don't need the extra performance of the 821 but instead want to utilize it's efficiency.

TLDR Google is going all in on the Pixel proving a very fast user experience while being power efficient!
 

lexcyn

Senior Member
Apr 4, 2010
706
723
Sudbury
So in theory once kernel source has been released we can just OC it back to "stock" frequency and get even faster performance with a hit to battery life. ;)
 

ramqashou

Senior Member
Mar 25, 2015
156
48
So basically the pixel xl nd the pixel have snadragon 820 with a different name and better efficiency, as a result the gaming performance is the same as on the lg g5 or the s7 for example, these pixel devices arent worth the extra 200$
 

mixedguy

Senior Member
Jul 18, 2011
124
55
So basically the pixel xl nd the pixel have snadragon 820 with a different name and better efficiency, as a result the gaming performance is the same as on the lg g5 or the s7 for example, these pixel devices arent worth the extra 200$

The smaller Pixel has the potential to out do both of those phones and the Pixel XL in gaming since it has a native resolution of 1080p. The lower the resolution, the higher frames per second possible in games when using the same SoC, assuming the game is made to run at your phones native resolution.
 
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Hoodeddeathman

Senior Member
Jul 23, 2008
230
55
Manchester
So basically the pixel xl nd the pixel have snadragon 820 with a different name and better efficiency, as a result the gaming performance is the same as on the lg g5 or the s7 for example, these pixel devices arent worth the extra 200$

In the current climate and with the 810 fiasco overshadowing can you really blame them for dialing it down? Perhaps the GPU is still clocked higher in the 821 and I'll take the efficiency as a perk. It's up to you what's worth $200 more but there are a few more bits less talked about included in the price.

---------- Post added at 07:11 AM ---------- Previous post was at 07:09 AM ----------

The smaller Pixel has the potential to out do both of those phones and the Pixel XL in gaming since it has a native resolution of 1080p. The lower the resolution, the higher frames per second possible in games when using the same SoC, assuming the game is made to run at your phones native resolution.

I'd rather have 1080p at 60FPS than 2k at 30FPS on a screen that size, however I think most games, at least the big titles, have adjustable resolution so I think the only difference will be battery draw.
 

mixedguy

Senior Member
Jul 18, 2011
124
55
I'd rather have 1080p at 60FPS than 2k at 30FPS on a screen that size, however I think most games, at least the big titles, have adjustable resolution so I think the only difference will be battery draw.

I agree, I wasn't aware you could choose your resolution in mobile phone games as I don't really play demanding games on my phone, I assumed it was like mainstream game consoles where the developer predetermines the resolution or just sets it to use the native res by default.

I play games on PC, so it's pretty cool that you can change the resolution on mobile phone games like you can on PC games.
 

Hoodeddeathman

Senior Member
Jul 23, 2008
230
55
Manchester
I agree, I wasn't aware you could choose your resolution in mobile phone games as I don't really play demanding games on my phone, I assumed it was like mainstream game consoles where the developer predetermines the resolution or just sets it to use the native res by default.

I play games on PC, so it's pretty cool that you can change the resolution on mobile phone games like you can on PC games.

As I understand it android has the capability and it's up to the devs to implement. The game can be rendered at whatever resolution and will then be upscaled. for example Warhammer Freeblade allows you to select which resolution to use and texture qualities just as you would in most PC games at the risk of losing frames however Need For Speed No Limits selects a pre-defined profile depending on device.
 

Gerrit507

Senior Member
Jul 24, 2015
538
278
Germany
As I said, underclocking doesn't automatically mean better effiency... If you would have a 820 phone you would know that. I experimented a lot with different CPU settings on my One Plus 3 and underclocking is not worth it because it only cuts of performance but does NOT increase effiency because your CPU is using max frequency like 1% of the runtime anyway... In more than two days 2,15 GHz on the big cluster was used only 49s on my OP3.

And that the 821 reaches a higher frequency doesn't automatically mean that the CPU has a higher quality. I know it would be possible that the 820s are only bad 821s that don't surpass quality tests but I don't think so because the 820 was released much earlier. Usually it goes the other way around, like on GPUs. Nvidia first releases the very high end models and then sells the crappy GPUs in the lower end models. I don't think that Qualcomm is like, hey we are picking out all really good 820s and pile them up to sell them as 821s... A 821 could be better and more efficient but it's not necessarily true. A good 820 could still be as good or even better than a 821, regarding effiency. Also think about AMD Processors a few years ago, whole cores where unlock able and there was still room for OC if you were lucky.
 
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Hoodeddeathman

Senior Member
Jul 23, 2008
230
55
Manchester
As I said, underclocking doesn't automatically mean better effiency... If you would have a 820 phone you would know that. I experimented a lot with different CPU settings on my One Plus 3 and underclocking is not worth it because it only cuts of performance but does NOT increase effiency because your CPU is using max frequency like 1% of the runtime anyway... In more than two days 2,15 GHz on the big cluster was used only 49s on my OP3.

When talking about efficiency I'm referring more to undervolting as appose to underclocking, it may be the case that they have chosen those frequencies because the 821 steps up in voltage beyond that point thus increasing power consumption and heat. We'll have to wait and see how the Pixel performs, but if that underclock means the thermal load is capped lower we will also see less throttling, ideal for daydream.

As an example I would refer to overclocking desktop CPUs, the architecture is different but how it responds to heat and power is not. beyond a certain frequency the CPU requires exponentially more power and generates exponentially more heat the higher you go.
 

mixedguy

Senior Member
Jul 18, 2011
124
55
The 821 only has a 10% performance increase when clocked at its max frequency, so even if Google did leave it at its max frequency, a 10% increase would be barely noticeable, if noticeable at all in real world use.

The 821 does have some features that aren't available on the 820, which is why Google probably chose the 821 over the 820. I found this info about two important features for the 821, that's not found in the 820 and quoted it below.



"One of the main reason why Google used the Snapdragon 821 in the Pixel phones is the Snapdragon VR SDK (Software Development Kit). This is entirely unavailable with the Snapdragon 820. The new SDK comes with advanced VR toolset to give the developers broad access to the internal architecture of the Snapdragon 821 chipset. This is extremely useful and fully compatible with Google Daydream platform. The VR SDK helps in the rendering of cutting-edge visual and audio which helps in state of the art Virtual Reality experience."

"Another important thing which is unknown for most people is about the camera improvements brought by the MSM8996 Pro. The SoC can simultaneously use two phase detectors for significant improvement in focussing quality and time. On the contrary, the Snapdragon 820 or MSM8996 only supports single PDAF (Phase Detecting Auto Focus) systems. The newer chipset extends the range of laser autofocus technology. This will substantially boost the laser-assisted autofocus systems of upcoming smartphones."
 
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Nitemare3219

Senior Member
Nov 24, 2010
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For some reason idont believe in overclocking, cuz it's beyond the device capabilities and it might cause some problems.

That's a very incorrect statement. The kernel determines the clock speed. Google could choose something like 0.5GHz if they were so inclined. The phone would run like ****, but in your eyes, the device is not "capable" of anything faster. It sounds like Google purposely underclocked these. If nothing else, you are absolutely 100% fine to clock it back to the speed that Qualcomm, the OEM of the chipset, intended it to run at. True overclocking can present problems, but I have overclocked my CPUs, RAM, and GPUs for YEARS with no issues and reaped plenty of extra benefits in terms of performance. I used to do it on my smartphones too, but it is pointless and wastes battery for almost every use scenario.

Google specifically chose 2.15GHz instead of 2.4GHz as specified by Qualcomm, either due to heat issues or battery life benefit. I am going to guess they realized that their incredibly light and optimized software does not need a 2.4GHz CPU speed - hell, my 6P is faster with a SD 810 than my Note7 with an 820 in day to day use for a reason, that reason being stock Android is incredibly quick and efficient.
 
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JasonJoel

Senior Member
Apr 23, 2008
1,783
570
That is true from the chip standpoint. What you don't know, though, is if google/htc designed the heat removal system to handle the additional heat produced at full clock speeds without throttling...

Sent from my Nexus 6P using Tapatalk
 
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lexcyn

Senior Member
Apr 4, 2010
706
723
Sudbury
That is true from the chip standpoint. What you don't know, though, is if google/htc designed the heat removal system to handle the additional heat produced at full click speeds without throttling...

Sent from my Nexus 6P using Tapatalk

The phone being a uni-body aluminium shell should help with that. My 5X gets mega hot when I run games or for extended screen on times, but the back is plastic. I think using the whole surface of the phone as an additional heat-sink so to speak could help with heat dissipation.

Either way - I hope someone tries to OC it back to "stock" qualcomm speeds. I will certainly try to see the results, that is, if custom kernels can be a thing with the Pixel.
 

ramqashou

Senior Member
Mar 25, 2015
156
48
That's a very incorrect statement. The kernel determines the clock speed. Google could choose something like 0.5GHz if they were so inclined. The phone would run like ****, but in your eyes, the device is not "capable" of anything faster. It sounds like Google purposely underclocked these. If nothing else, you are absolutely 100% fine to clock it back to the speed that Qualcomm, the OEM of the chipset, intended it to run at. True overclocking can present problems, but I have overclocked my CPUs, RAM, and GPUs for YEARS with no issues and reaped plenty of extra benefits in terms of performance. I used to do it on my smartphones too, but it is pointless and wastes battery for almost every use scenario.

Google specifically chose 2.15GHz instead of 2.4GHz as specified by Qualcomm, either due to heat issues or battery life benefit. I am going to guess they realized that their incredibly light and optimized software does not need a 2.4GHz CPU speed - hell, my 6P is faster with a SD 810 than my Note7 with an 820 in day to day use for a reason, that reason being stock Android is incredibly quick and efficient.

That's true i can't
Deny the power of stock android, but there are many other OEM custom skins that are well optimized and are plenty fast such as sense and Lg ux 5.0 and even the oxygen OS
 

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    From what I have read the 821 is a 820. The 821 is just higher binned 820. When they make chips they are not all the same. Some just are a little more efficient than others do to very minor differences in the chips. So a high binned 820 can handle a higher clock speed while using less power are turned into 821.

    So Google decided they wanted to go with the 821 because it is more power efficient than a 820. But it seems Google thinks the speed of the 820 is fast enough to provide a good snappy user experience. So they are doubling down on efficiency by clocking these high binned chips down to the same as the 820. So say the 821 is 5% more efficient at stock speed over the 820. The 821 might be 10% more efficient at the same clock speed at the 820 while delivering the same speed as the 820. So they are sort of doubling down on efficiency over performance.

    From the hands on I have seen everyone has described the phone as very fast. This is likely due to Google optimizing Android to run on the pixels hardware. Much like Apple does with the iPhone. Also the Pixel has some hardware features that might not show up on a regular spec sheet. It has some improved touch screen latency and faster storage. Because of these factors Google decided they don't need the extra performance of the 821 but instead want to utilize it's efficiency.

    TLDR Google is going all in on the Pixel proving a very fast user experience while being power efficient!
    2
    The pixel XI and the pixel are packed with snadragon 821 chipset wich supposed to be clocked at 2*2.35 kryo & 2*2.0 kryo but both pixel phones are clocked at 2*2.15 kryo & 2*1.6 Kryo which is exactly the same as SD820 on Lg G5 and the s7 so if someone knows what is the difference between the cpu in the pixel phones and the regular snapdragon 820 please write it down
    2
    Apparently there a 2 versions of the 821. Google chose the lower version they did not underclock it. Good article on XDA News.

    http://www.xda-developers.com/a-loo...he-snapdragon-821-in-the-google-pixel-phones/
    2
    No one has trapped me into anything. I primarily use my phone as a phone and for texting. Wanting to ALSO play some games on it is my preference/desire.

    And for you console comment... I can't exactly take my PS4 on the train, into the doctor's office, etc - now can I?

    Sent from my Nexus 6P using Tapatalk

    Or the toilet...
    1
    I have the OP3 and the phone is clocking to max. frequency very rarely anyway. So there is no reason to clock it down for better efficiency.