Dude, That particular 4870, considering it's used should go for no more than $115 if you buy it from your friend. Hell, my 4870 I bought used for $75 and it is a mighty good card. But unless you don't think your power supply can handle it, go for the HD5870 as it's twice the card of the 4870. But just so you don't think the 4870 is a bad card, I do max EVERYTHING I own on STEAM at 1080p at well over 30fps. Just check my games list lol.