I recently ordered a Dell Optiplex GX620 and it comes with a 305 Watt proprietary power supply. I bought a Geforce 6800GT for the computer and the video card recommends at least a 350 Watt psu. I went out and got a standard ATX PSU and it is exactly the same size as the PSU in my Dell only it's a 20-pin connecter and the Dell is 24. Not only that but I heard that a standard ATX PSU will fry the motherboard and/or the power supply itself. I've heard that I'll need this "Dell to ATX converter" to fix the problem...but the converter has only 20 pins as well. I'm also not even sure if the converter is compatible with my system because my Dell motherboard doesn't have this extra connecter...

http://www.endpcnoise.com/cgi-bin/e/dellconverter.html
(in the picture there's another little connecter on the left...my Dell motherboard lacks it)

I don't know what to do...I've done a lot of research on this and the results vary. Some people think the ATX PSU will work just fine despite it having a 20-pin connecter as opposed to my Dell's 24-pin connecter. Some think the converter will solve the problem. All I wanna do is get a damned power supply so I can use this video card...Dell doesn't even carry any higher wattage PSUs for this model. WHAT CAN I DO?!1@#!