I wanted some advice on gpu's for new build. I can't decide over Radeon HD 4850 or Radeon HD 4870. I didn't like what I read about gtx 260. http://www.tomshardware.com/reviews/radeon-hd-4870,1964-18.html Any advice would be great. What are good brands for this , I heard visiontek and sapphire was good, but never paid much attention in past. What is GDDR3 or GDDR5 ?