unless you know your 300w is top-quality (units in hps, dells, compaqs, etc are NOT top-quality). the card will work intially but you'll probably have problems (sporadic crashes, games not looking right, and others).
I just bought a PNY 7900GS and was wondering if i really need the minimum required 350W Power supply to run the card. I have a 300W, and am not sure if the 350W minimum is for using Dual Monitors. Some one help! DO I REALLY NEED A 350W POWER SUPPLY!?