Best card for Video editing

[Kkkk1]

Hi folks,
I am buying a suite of PC's at work with the following spec for Video editing:-

Core i5
4Gb RAM

My question is what video card would help for video rendering. I don't want to use the onboard graphics but I don't have the funds to change the PSU as well as the GPU.

Any suggestions would be really helpful.

 

[xtreme5]

gtx 460.

 

[Kkkk1]

Would I need a better PSU though?

 

[xtreme5]

what psu are you using?

 

[Kkkk1]

It's a standard 275W on a Dell Optiplex PC

 

[xtreme5]

of course you must buy a new one something like cooler master 550w