System is a custom built, with all new components. CPU: Phenom II X4 955, Rev C3 MB: Asus m4a79xtd evo - 790x Chipset RAM: 2 modules, Kingston KHX1600C9D3BK2/4G 4GB DDR3-1600Mhz PSU: Lc-power 600 w GPU: PowerC Ati radeon 4890 1gb ddr5 So the problem appeared when I installed win7 64bit. No problem what so ever on XP. The games runes about (50-100) fps depends on the game, with apsolutly no lag but accompanied by some a kind of jerky motion. Some kind of frame problem. Relay i don't know how to describe it.I tried to reinstalled (formatted) the whole system. fresh drivers for the motherboard and graphics and still nothing.Updated my bios. Tried win7 32bit to. But when i downgrade to Xp, problem simply disappears. Does anyone know what the problem is and how to solve it? ...i don't want to return to Xp again The strangest thing...when i play battlefield bad company 2 i have around 70-100fps and choppy gameplay. but when i run some background process like fraps ( movie capturing with f9 -function on ) that lower frame rate in game , problem disappear . How strange is that ??