Yes, I would say that you need to upgrade your power supply box and fan setup before running any high graphical games. My suggestion would be to buy a 900w power supply or higher. http://www.newegg.com/Product/Produ.....mp;x=0&y=0 or look around the website there or at places like Best Buy for something like.

See, the problem is, you have a higher power supply already but many other things on your computer are using the power as well. So, try a 250 or 2.50 percent mathatical formula when thinking of the power given to a graphics card and to the rest of your computer. 650+250=900. This forum gives power to all function of the computer and should fix your problem. Now, i'm not a computer wizard but if that doesn't work I'd say try a 1050w power supply or it's just your graphics card is overclocking games and that means you'll have to reinstall the games. The power supply scale is 650w, 700w, 750w, 800w, 850w, 900w, 1000w, 1050, 2000w etc. So remember, add 250 to the number of your graphics card power to get the total number need for full operation. I hope this helps.

My suggestion would be to get a better cooling system, if it's locking up it's more than likely its running alot of heat.

Then again, it could be a power issue, depending on how many peripherals you have attatched to your PC. In general if the card suggests 650W and you have an 850W power supply, then this should be more than enough (but that depends on what you already have attatched to your PC). If you have alot of peripherals attatched, try taking some of them out til it works and see if it helps, if so upgrade the power pack.

Another option would be to switch to Nvidia... I had nothing but problems with ATI cards in the past >_>.