Performance problems on Unreal Engine 3 games

Hello everyone!

I have an issue about Unreal Engine 3-using games. Except HAWKEN, Bioshock and Batman Arkham Asylum; i have extreme stuttering in such games. I found that framerate smoothing causes that but even i turn it off in ini files of those games, that's still the same. 1024x768 everything turned off/low is same, so i believe the problem is something else. I have a decent rig and also i can play most of games without a problem.

My rig:
Operating System
Windows 8 Single Language 64-bit

CPU
AMD A10-4600M
Trinity 32nm Technology

RAM
8,00GB Dual-Channel DDR3 @ 798MHz (11-11-12-28)

Motherboard
AMD PLCSC8 (Socket FT1)

Graphics
Generic PnP Monitor (1366x768@60Hz)
512MB ATI AMD Radeon HD 7660G (Toshiba)
1024MB ATI AMD Radeon HD 7610M (Toshiba)
CrossFire Disabled
Currently using this driver

Storage
596GB TOSHIBA MK6475GSX (SATA)

Please enlighten me with your knowledge. Thank you.