Crossfire 4770 power supply?

I think you should upgrade your PSU.
Get atleast Corsair VX550.It will also handle any OC.

The general rule of thumb is that a high quality 500 to 550 watt power supply with sufficient current (amps) on the 12 volt rail(s) can easily handle any video card made. A high quality 700 to 750 watt power supply with sufficient current (amps) on the 12 volt rail(s) can easily handle two video cards operating in dual mode.

With the ATI Radeon HD 4770 graphics card the rules change because the cards are energy efficient. They do not use very much power. Tom's Hardware recently published an article about using two 4770 cards in Crossfire mode. The cards were tested in an Intel Core i7 system. The power consumption was measured at the wall outlet. That means the results included power for all the system components, not just the video cards. The system used a grand total of 190 watts at idle and 252 watts at load. Pretty impressive.

Your power supply is not all that great and it is not very efficient. Here is a link to a technical review:

http://www.hardwaresecrets.com/article/332/9

I suggest you upgrade to a high quality power supply. Corsair, PC Power & Cooling, and Seasonic are brands with reputations for high quality psu's that are stable and reliable. If you are on a budget, then an Antec Earthwatts psu would be a good alternative.

We may wind up seeing new graphics cards and cpu's that are even more energy efficient. I think the 4770 is just the beginning. The big boys have jumped on the green bandwagon. We may even see a move from 45nm technology down to 32nm technology. Intel, AMD, and other manufacturers are in a race to see who can bring the 32nm technology to market first. It looks promising.

Good Luck!