4890 Card goes Black

Hi All -

I am using the following:
HIS Radeon 4890 1GB (256-bit PCI-E 2.0 x16)
AMD Phenom II X2 550 (B.E.) 3.1 Ghz – at stock speed … did not unlock it
GIGABYTE GA-MA790X-UD4P
4GB SDRAM DDR2 1066 (PC2 8500)
CORSAIR 850TX 850W
LG 24" LCD (W2486L)
Windows XP - Home Edt (SP3)

Card works perfectly we no load is being put on it. Can watch DVD's (Non- Blu Ray) without a problem. Also, can have dual monitors going at the highest resolution and no problems.

When trying to play any games the problem occurs. Using only 1 monitor, after 60 seconds of game play the screen goes black for about 10 seconds. It appears to go into recovery mode and drop the resolution to a minimum. The screen will come back up and I can continue game play for about another 30 seconds until it does it again. This has happened to me with playing Crysis, Crysis Wars, Team Fortress 2.

I did run PCMark05 and it had no problem as long as the Video settings in the Catalyst Control were set to "Performance" as opposed to "Quality". I ran a bunch of the auto-setting features in the software and all the tests “passed” - no such luck.

I have the card in the PCIe x16 slot as Gigabyte recommends. Updated all the drivers to the best of my knowledge. I have the same issues using a 19" SyncMaster or a 24" LG LCD. I am using a DVI cable to connect.

Sent an inquiry off to HIS, when I hear back I will post it.

I already tried each LCD alone and in both DVI's out on the card and no luck. I have 2 LCD's (19" Samsung and 24" LG). To the best of my knowledge and DriverCure, I have installed the latest drivers for the LCD's.

At first I had both LCD running and card would go black only during gaming when the load was high. I disconnected the 24" trying the get the smaller LCD to work would be easier ... no luck. Then thinking maybe the 24" LCD since it is newer would run better by itself ... no luck.