Windows 7: ATI 1900XT Freezing ingame

I installed the RC 7100 and when i start a game (Empire total war) after 3-5 min of gameplay (especially in battles) the game freeze and i can hear the sound and move the cursor but the system doesnt respond anymore needing a reboot.

I noticed that this is related to overclocking because i use rivatuner to control the fan and when i was ingame the clock was 620 core and 720 memory the game freezes in 1-2 min, after i underclocked to 500 / 600 (stock clock) the game take a little more time 3-5 min but end up freezing again, ive already tried to underclock but the problem persists only taking a little more time to appear 7-10 min.

Ive already tried to not use rivatuner but the problem persist.

I tried to install all drivers version for radeon 1900x since 8.2 to 9.3 (the last driver for this old cards) and the problem remains there.

I dunno what to do and btw ive already updated bios to 1701 (last update).

My specs
ASUS M2nSLI Deluxe
Phenom 9850
X1900XT
4gb 800mhz


Any help will be very apreciated.
Sorry for the bad english, isnt my mother language.