Fix for slow SD card speed with HTC's Froyo Kernel
There have been quite a few complaints about slow SD card speeds with Froyo/Sense ROMs (e.g. http://forum.xda-developers.com/showthread.php?t=778748
I've looked into the problem and discovered that the poor performance is due to HTC reducing the readahead settings in their kernel.
I've attached a prebuilt kernel (as a flashable zip using Koush's AnyKernel) and a kernel source patch that fix this. Let me know how you get on
EDIT: if you prefer Richardtrip's kernel to the stock one, use the update zip here
, or v5 or later of his kernel, instead of kernel_2.6.32-frankoid.zip
To see whether your kernel needs the fix you need to run a command with your phone plugged in to your computer. On Linux and OS X you need to include quotes, like this:
adb shell 'cat /sys/devices/virtual/bdi/179:0/read_ahead_kb'
If you are using Windows don't include the quotes - run this:
adb shell cat /sys/devices/virtual/bdi/179:0/read_ahead_kb
If it returns 4 then you need the fix. If it returns 128 you don't
If you are a developer and you'd like to incorporate this fix into your ROM without having to change the kernel see this post
for instructions on how to edit init.rc to change the readahead setting.