crossfire a pair of 4870x2

Raventon

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Jul 29, 2008
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does anyone know is it possible to crossfire a pair of 4870x2 on the rampage formular with intel x48 chipsets?and how well well it scale?

cos if it dun work i will be getting a pair of 4870 instead and will not wait for the launch of 4870x2. thanks
 

SSChevy2001

Senior member
Jul 9, 2008
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Should be no problem, but the question is will it be worth it? Honestly anything more than 2 GPUs is really just a waste. Pair of 4870 would be nice, but 512mb between 2 GPUs is a little limited. You waited this long you might as well wait it out a little longer. Here's the only review showing 2 4870x2 running.

HardOCP 4870x2 Review
 

Raventon

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Jul 29, 2008
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a crossfire with a pair of 4870with 512mb each isn't it 1gb? or it only uses the 512mb from one card and the ram on the other card is unused?
 

Sylvanas

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Jan 20, 2004
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Originally posted by: Raventon
a crossfire with a pair of 4870with 512mb each isn't it 1gb? or it only uses the 512mb from one card and the ram on the other card is unused?
The amount of ram each GPU can address is 512MB, the memory is not pooled. The 4870X2 is a 2GB card in total, but each GPU adresses only 1GB, which is it's 'Framebuffer'. In many respects the 4870X2 is a better choice over two 4870's. The reviews should be out in a week or so last I heard so you will have more info to go on then.
 

Raventon

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Jul 29, 2008
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i guess i should wait for the 4870x2 then.btw i am having my e8500 overclock to 4ghz.Will it be limiting the crossfireX if i were to install a pair of 4870x2(meaning 4GPU)?or should i go quad?if i am going quad is it better to get the qx9650 or the qx9770?
 

ccubed

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Jul 4, 2008
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There will probably be an ATI HD 4870 with 1 gig of RAM just like there is now an ATI HD 4850 with 1 gig of RAM. If you really want to wait you can hold out for the Crossfire of the 4870's with 1 gig RAM. They will probably also have superior stock cooling.
 

Majic 7

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Mar 27, 2008
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Do you run Vista. I am pretty sure it's needed to run two X2s. Two 3870 X2s needed Vista, it's considered CrossfireX, more than two GPU's.
 

Raventon

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Jul 29, 2008
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im running xp pro,if needed, i could upgrade to vista since i have a copy of vista ultimate64.my main concern is that my e8500 will be a bottleneck in the CrossfireX setup.
 

SSChevy2001

Senior member
Jul 9, 2008
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@raventon - Sylvanas explaination is right, but what he forgot or didn't add is that the memory data is copied between GPUs, making only half usable.

Your dead bent on wasting money on 4 GPUs? A 3.2Ghz C2Q will CPU bound just one 4870x2, again another will be a waste. I doubt you'll see much if no gain even with 4Ghz C2Q. The best you'll see is higher AA, not really any additional FPS. If you looked at the HardOCP page I linked before you would see that.

Edit I wouldn't worry about crysis score on that page. AMD/ATI said their working on improving the FPS with that game. Also Crytek is also working on warhead, which should be more optimized.
 

Majic 7

Senior member
Mar 27, 2008
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Another thing is that so far 4 GPUs don't scale well at all. They seem to hit the wall at three.
 

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