Lagging all the way frame by frame

Hi Guys,. I am experiencing issue with my computer. All of games are lagging like hell. you have to make it minimum to make it run decent enough my specs is

Cpu: Athlon 2x 250 3.0 Ghz

Board: Biostar A780L3B

Ram: Ovation 1333mhz ddr3 4GB x 2

HDD: 500GB Seagate & 250GB Seagate (not sure about the rpm's)

GPU: EVGA GTX460 SE 1GB 256bit ddr5 and ATI Radeon™ HD3000 Graphics, On Board Graphic Max. Memory Share Up to 512 MB

PSu: FSP Raider 550w 80Plus-Bronze

Operating system: Windows 7 ultimate&Home preimium (both 64 bit) & Windows XP sp2 32 bit (Tried all of them)

Driver: Nvidia 301.42 and directx11 tried to run earlier drivers as well

Tried all the games like 2k12, ASC Brotherhood, Cysis2, COD modern 1, 2, 3, Black ops, NFS, GTA IV and all other games (which runs on my other computer, athlon 2x 250 3.0 Ghz , gtx 550ti and 2gb ddr2 run without any problem at all. 1360x736 reso and high to medium settings and I am getting 20 to 30 fps minimum) however on my new board and GPU I am really having problems playing them, I am lagging frame by frame running. I am not passing 30 above fps even at 2k12 medium all settings with 1366x 736 reso.. I tried to play online games as well that doesn't require good gpu but Fps is still low and you can see lag every movement. (it only happens when you are playing) not on desktop or browsing... Drivers on the board is updated as well. I tried to use the gtx460 on a weaker cpu dual core 2.0 with 2gb ddr2 and it can run my online games and other games decently, fps is not high but it is not lagging every second. Any Idea what seems to be the problem?