Alienware M18x R1 Heating Issues

Hi, 

I purchased an M18x R1 roughly eight months ago, specs are as follows;

Dual 580M's, 8GB 1600MHZ RAM, 2x 750GB HDD's and an i7 2920XM with factory overclock.

Now, to the issue. I play a lot of games, like a lot, but until recently I was only playing Counter Strike: Source, which has relatively low resource requirements. When playing games in general for either long or short periods of time, my fans hardly spin up at all. In fact the only time i've ever heard my fans really spin up was when i flashed my BIOS to A05, at which point they became very audible and my system cooled immediately. When playing games this instantly becomes a problem because instead of my fans spinning up my entire system heats up immensely and then goes into what i have dubbed low performance mode, my fps dropping from an even 250 to an unacceptable 9. I'm not sure if there is a fault of some sort in my system, though i have my doubts about that because my fans in fact do spin up when i open a BIOS flasher. I would love to hear wether I am correct in thinking that this is the cause of the issue and more importanly wether there is a fix for it. 

Thanks.