Hello, my friend gave me a Dell computer for free (he bought an Alienware with Nvidia 7950 GTX, not quand. He's starting a video editing business)!
Anyways, the Dell I got only has a mere 305 watt power supply and the Graphics cards I want to buy both require 350 watt minimum (ATI X1300 Pro Or BFG Geforce 7600 GS OC). Should I upgrade my power supply or can i run thses cards safely? If i need to upgrade my ps, what wattage would be the right choice (any decent recommendations?)
If the PC has PCI-express (which I'm assuming it does, since the 7600 GS OC you linked to is PCIe), I would suggest you get this card instead of the x1300 or 7600. It will offer much better performance at about the same cost. Its only drawback is that it doesn't support Shader Model 3, but:
a. Hardly any games use it
b. It's barely noticeable
c. The X1300 and 7600 GS OC aren't powerful enough to use it anyway
As for power requirements, that depends how much you have in your system. Additional hard drives, optical drives, etc. can increase the power load on your system, so you might need a new power supply if you have 4 hard drives and 2 DVD burners.
First, upgrade your psu. You need at least 450 wt to do much, with about 550 wt if you want future upgradability. Look to Antec, Enermax, Seasonic, or Hyper for good supplies. The bad thing is that some Dells only will accept Dell designed parts, so if you have one of those, you'll either have to buy a Dell psu or you'll have to modify the case.
Second, a X800 GTO would be a better card than those you listed. If you're stuck between the two listed, go for the 7600 GS.