Love my 4870, just is a little too long, interfers with 1 HHD bay. Requires 2 PCIe plugs, whereas 5770 only 1.
Same cards, 5770 = newer, Dx11, less power.
I'm only using one alienware 22 inch monitore,so no need for eyefinity, and I play crysis halo 2 call of duty 2, so don't really need dx11, exactly how long is that card?
THe XFX Radeon HD 4870 is 9.5" long.
The XFX Radeon HD 5770 is 8.5" long.
I believe other card manufactures will be very close to the same. Check the "specifications" area on the retailers site for each card.
Both have "plugs" for 6-pin PCIe power on the outer edge, opposite the DVI output. The 4870 needs 2, the 5770 only needs 1.
Keep the 4870. DX11 is not going to change things as 3 games support it. (2 more than dx10 lol). It looks impressive, but like physx the performance hit (fps) and the need to lower things like AA and other "eye candy" probably isnt worth it right now.
But power is a lot lower on the 5770.
Seeing that you already have the 4870, keep it. It is a good card and should serve you well in the end.
By the way, what games do you play and at what res.?
I play at 1600 by 1050 but my monitor will handle full 1080p 1920 by 1080, crysis at high settings, company of heroes, call of duty, dirt 2 etc..