WARNING: I do not know if all Android ROMs make use of /system/etc/init.d scripts, so this may not work for you. Use at your own risk!
ROOTED STOCK ROM USERS: Unfortunately, it seems that you folks will not be able to make use of this tweak, since it seems that the stock ROM does not utilize init.d. I do not have access to a phone running the stock ROM, so am not sure where in the boot process we can alternately insert a script to apply this tweak upon every bootup.
First, check to see if you even have an init.d folder.
adb shell ls /system/etc/init.d
Your output should look something like this:
c:\Incoming\Android>adb shell ls /system/etc/init.d
00banner 02firstboot 04apps2sd 99complete
01sysctl 03modules placeholder
If you get "ls: /system/etc/init: No such file or directory" as a result, then you don't have this folder and SHOULD NOT CONTINUE.
DOWNLOAD FLASHABLE ZIP HERE: Courtesy of akazabam @ AndroidForums
sdreadahead-signed.zip
Boot into recovery, flash, reboot.
After rebooting, run the following to double-check everything worked properly.
adb shell cat /sys/devices/virtual/bdi/179:0/read_ahead_kb
If it says 128, you're done! I hope this helps some of you out!
Also this speeds up the phone considerably especially if you are using APPS2SD...
xda-developers - View Single Post - SD card speed fix (5Mbps to 15Mbps)
http://forum.xda-developers.com/showthread.php?t=921530
Sd Card Read/Write Tester .apk attached