2 x 4850 or 1 4890

Hi Tacoboy,

I think it may be closer than you'd think, but I'm relatively certain two 512MB HD 4850s will outperform a single HD 4890; both configurations will have 1GB of video memory available to them and will handle a 1440x900 resolution fine.

Unfortunately it seems like it's impossible to find any articles directly comparing HD 4890 vs 4850 CrossFire performance so I can't provide any proof, however, I think regardless it is the most price effective solution for you to take.

Also, as a side note, Supreme Commander likes beefy CPUs.

+1^
2xHD 4850 perform better than a single HD 4890 but Supreme commander will mostly benefit from a good CPU,i think a single HD 4850 can handle Supreme commander on high for that resolution.
What is your CPU ?

I'm using an AMD 2.8GHz quad core cpu, with 4GBs of memory and Vista 64.

AMD Quad core 2.8GHz

Even if it's a Phenom I it should be good enough seeing that it at least has four cores and the game makes use of them.

A combination of one HD 4850 and your CPU can handle Supreme commander on high settings on 1440x900 resolutions,have run it yet ?

I would think your current setup should be fine for playing that game on high at that resolution.
But, to answer your question, 2 HD4850s are a lot better than an HD4890 with performance similar to an HD5850.

Agree with all of you guys, 2x HD 4850 will outperformed a 4890.
Also, your system is just strong enough to play that game on HIGH setting...

ehm actually
2 hd 4850's are a little stronger than the Gtx 280, and the Hd 5850 rapes the 280, so that doesn't make the performance similar....

2xHD 4850s perform pretty much like a HD 4870X2/HD 5870:
http://techreport.com/articles.x/15293
Its a little old article but it compares 2 HD 4850s with 1 HD 4870X2(Which performs like a HD 5870 in almost every game)