Nvidia make some of the best graphics cards around.

The Nvidia 550 ti is a very good card from their range.

I think it has 512 mega bytes! I checked on websites (Nvidia) and found out.

No.

GoForce

Nvidia is currently the leader in gpu performance with the GTX 560 I personally have dealt with both companies I tend to stick to Nvidia seeing as about a month ago my Overclocked GTX 8600 died so I decided to buy a Xfx ati raedeon 5770 HD and that was DOA right out of the box so I traded it in for an Nvidia GTX 460 and the second I installed it it worked just fine Nvidia has always had the faster shader clocks allong with core clocks but you can't beat atis for the price I mean the gtx was like $260 while the raedeon was $180 it's always about preference and budget the best manufacturers are gonna be Nvidias actual cards (not like pny's or bfg tech's) or EVGA if ur going Nvidia. If ur going ati then XFX or Asus.