All P500 users will be aware of this bug. When you play touchsceen games you will notice a lag when the screen is touched. I noticed this more in the game Assassins Creed which has virual touchscreen controls. This is due to the bug in the stock kernel that causes the CPU usage to shoot up all the way to 100% whenever the screen is tapped.
One of the XDA member mik_os has come up with a fixed kernel that addresses this issue. Donwload his kernal and flash it http://forum.xda-developers.com/showthread.php?t=929941
Or upgrade to Gingerbread