FX 5900 abnormalities

[biostud]

I've just switched my Ti4200 to a GFFX5900XT and when i start a game like the UT2K4 demo it freezes for like 15-20 secs, and then show the graphics corrupted. When I tab out and in everything is fine. Any ideas?
I've re-installed drivers and DX9.0b

System:
Athlon 2100+@2083Mhz
2x512 Corsair Value Cl2.5
MSI Delta-L nForce2 (latest BIOS v5.6)
Club3D GFFX 5900XT (8x AGP, fastwrites + sideband enabled)
WinXP SP1
Detonator 56.56 (Also tried 53.41) WHQL

 

[Futher]

Not sure, I have a Gainward FX5900 Ultra and UT works perfectly on it. Did you connect the power to the videocard? If not, the fan won't turn and it could overheat. Try reinstalling the drivers for the videocard, not DX.

 

[biostud]

It runs fine for the rest of the game and I have re-installed the drivers. It has same problems in other games (C&C Generals), but not all. It's only at startup there's a problem otherwise it chucks along just fine. The powercord is attached otherwise I couldn't boot my system.

 

[sandorski]

You re-installed drivers, but did you remove the Ti4200 from the Hardware Profile?

 

[biostud]

Yup I did that before installing the new card. (I just checked and it doesn't show up on the hardware list either)

 

[Tango57]

What's the power rating on your psu? Some 5900 cards run unstable unless you have a psu that can supply 450 watts or higher to the system.

 

[biostud]

420W So it should be fine. Actually the problem occurs everytime I start a new round in UT2K4, or load a saved game in C&C generals. But when it's first running everything is fine.