BF2/PR Lag like hell

[fabioxxxx]

After upgrading my pc i started to get some annoying lags not related to ping.

at first my new memory did not run at 1600 , i only adjusted the voltage and the multipliers ,still it run at 1333, but gaming was fine... so i played a few weeks like that.

then i enabled XMP ,memory went to 1600 and the lag started... only changing my memory back to 1333 made the lag stop. (disabled xmp)

Windows 7 64
ASUS P7P55 PRO
I5 750 2.6Ghz
8 GB (2x 4GB 1600 CORSAIR DOMINATOR)
ATI RADEON HD 5770
SSD CRUCIAL M4 120GB