ATI vid card selection: 4890, 5770, 5850?

[jomofro39]

Hello everyone.
I had recently built a system in October, and got with it a XXX 4890 from XFX. Well, it recently died on me, so I RMA'd it, but in the meantime, I bought a 5770, which I am thus far very happy with. I am considering selling the 4890, keeping the 5770, or possibly selling both of them and upgrading to a 5850. Is it worth it to get a 5850 or just wait until I need to upgrade and xfire with another 5770? I have to get a different 5770 later anyways because I want to eventually do eyefinity, and mine did not come with a displayport (poor research, quick decision). So I would sell both the 4890 and 5770, get another 5770, and eventually get another 5770 for xfire. How important is the 128-bit vs 256-bit memory?
I am pretty sure you need the same manufacturer and model of cards to xfire, right? Or am I out of my mind? Any advice is appreciated, I am kind of stumped with what to do here. Thanks!

 

[rolli59]

If you are happy with the performance there is no need to upgrade specially if your resolution is 1680 x1050 or less. But if you want to upgrade the HD5850 is a solid choice.

 

[fisshy]

Tough Decision. Personally i Would Go for The 2x 5770 But only if your MOBO supports 2x16 bit PCIE Channels.
Other wise The 5850

 

[soundefx]

Honestly, I would try and get the 5850.

The 5850 would give me a little more power than the other two you listed so that I wouldn't have to upgrade as soon as if I had the others.

Also when it is time to upgrade, the second card should be cheaper and the power from both of them would last me a little longer as well.