Poor performance with 5870m in crossfire

Hi,

I have recently purchased an Alienware m17x with dual 5870m in crossfire.

Initially I had issues (crashing on battery etc) that were resolved by a BIOS upgrade as well as flashing the video BIOS to the latest versions.

I have since noticed that there are serious performance issues in games when crossfire is enabled. The games I play are Bad Company 2, Fallout New Vegas and Black Ops (I am aware of the limited crossfire support for this one).

I have tried dozens of different catalyst drivers, hotfixes and profiles but nothing appears to increase the performance in games. However, as soon as I disable crossfire, low and behold the game plays well.

Now i could (and have) just use the laptop with crossfire disabled, however I dont feel that I should have to do this especially for in the future when one 5870m just wont cut it.

I have noticed (using GPU-Z) that when crossfire is enabled, the GPU usage is actually quite low (30% ). However, when crossfire is disable, the GPU usage is where you would expect it to be (90%-100% on one card obviously :).

Also, I find that my primary GPU runs very, very hot (often around 90 degress in games!).

I am unsure as to whether there is an issue with the GPU setup in my machine or whether there may be issue with PSU providing power,

Any suggestions are welcome, because I am well and truly out of ideas.

Regards,
Douse