HD4870 NOT entering performance mode, Help!

[yonef]

Hello,
I've recently bought a PowerColor HD 4870 and install it, and as soon as I run Crysys Warhead I've noticed that it is performing very bad! Then I run GPU-Z and keep it active while I play a bit. The problem is that while I play the Core Clock is still 500 Mhz ! It happens also on GRID and Mass Effect; BUT it works fine on Devil May Cry 4 and UT3.

Is There any way I can force the GPU to enter performance mode?

P.S. It's doesn't matter how much I overclock the GPU it still runs on 500 Mhz

My card is PowerColor PCS+ HD 4870 512MB GDDR5 http://www.powercolor.com/eng/products_features.asp?ProductID=2304

 

[yonef]

Update:
Is this possible because of the insufitient power supply? I have 600W PSU. Is it enough? and if it is not, can it couse this problem?

 

[spathotan]

600W is fine. Do you have the power plugs hooked up to it?

 

[LAN_deRf_HA]

Are you playing the games you're having trouble with in windowed mode? That's how it determines what speed to set the core at in the 48xx series (the exception being the 4870X2).

 

[yonef]

Yes, I hooked both plugs in (I tried with only one, but the card didn't start at all) Now I have only the radeon hooked in one of the PSU rails which is 35A and everything else is powered from the other rail.
No, I play the games only in fullscreen mode but the problem persists.

NEW UPDATE:
I have moved to the older drivers: catalyst 8.8 and something strange happens again
when I run crysis warhed, the framerate is the same as before but now the radeon enters in perf. mode (800Mhz) but the GPU load stays in 50-55% ! As I understand, if the GPU-load is less than 100% it means that it didn't works at full power.
What could cause this? And how can I force it to 100%
P.S. on some other games it loads to 100% and the performance is stunning.

 

[lunyone]

You may still have a PSU/GPU heat issues. What is the exact PSU make and model? Not all PSU's are made the same. How old is the PSU too? It makes a difference too, since you lose about 10% total power due to capacitor aging.
My first guess is that your GPU is running pretty hot, so it's throttling the core speed to control the temperatures.
What is your case too and the rest of your specifications? This could also show some light on other possible issues too.

 

[yonef]

My PSU is 7 months old, this one: http://www.ebuyer.com/product/127861
and The GPU temp is about 60 C, mem temp ~ 65 on playing crysis. (but it is loading GPU only on 55-60%) I think it is prety much cool for 4870.

P.S. I have tryed Crysis on XP (I have XP on my other HDD) and there everything is ok, I mean: 1680x1050 everything on Enthusiast - 25-40 FPS.
...smells like a driver problem ?!