two 512 4870's in xfire vs a 4870x2

[Darkrage]

If one where to go from two 4870(512) in xfire @8x to one 4870x2 @16x would there be a noticeable difference in performance? Or would it make more sense to go to something like a gtx 295?

 

[thilanliyan]

Don't get the 4870 512mb version. I myself would go for 2x4870 1GB but that's more because of size constraints. If you can get the x2 for cheaper then get that instead of the 295 since they are comparable in performance once you up the res and IQ.

 

[dguy6789]

There's no real reason to get two 512MB versions. Any setting that the 4870 512 can't run smoothly would also take more vram.

 

[Darkrage]

but if you already have the 512's? would going to the X2 give better performance?

 

[Denithor]

Depends on your resolution.

Check out the last two charts on this page. Compare the difference of the 512MB vs 1GB cards. Note the only difference is 2xAA vs 4xAA. If you're running ultra-high resolution & happen to like heavy AA you could exceed your frame buffer, forcing the video card to access system memory (far slower than VRAM on the card) and bringing your gaming experience to a grinding halt.

Same thing happens in Fallout 3 with resolution as low as 1680x1050 if you enable 8xAA (look at the minimum fps). Compare minimum fps for the 1GB & 512MB cards at the higher resolutions & heavy AA.

And just expect this to get worse going forward as games get more & more texture intensive.

 

[lavaheadache]

Originally posted by: Denithor
Depends on your resolution.

Check out the last two charts on this page. Compare the difference of the 512MB vs 1GB cards. Note the only difference is 2xAA vs 4xAA. If you're running ultra-high resolution & happen to like heavy AA you could exceed your frame buffer, forcing the video card to access system memory (far slower than VRAM on the card) and bringing your gaming experience to a grinding halt.

Same thing happens in Fallout 3 with resolution as low as 1680x1050 if you enable 8xAA (look at the minimum fps). Compare minimum fps for the 1GB & 512MB cards at the higher resolutions & heavy AA.

And just expect this to get worse going forward as games get more & more texture intensive.

I agree completely. The hd4870 is adequate up to 1920x1200 and sometimes beyond as long as sometimes you don't mind playing without AA. Crossfiring them will definately help out in a lot of situations but will not increase your IQ because you will still not be able to use AA when you couldn't before. I bet Crysis will become a lot more enjoyable though. I know a single hd 4870 played relatively smooth on high @1920x1200, but I can imagine 2 of them would be great.