Crossfire - 2 x 280x - 2nd card not working

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Jonathan Cave

Jonathan Cave

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Oct 17, 2013
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Thank you for taking a look at this thread here's the issue:

I got a 2nd 280x today and installed it with the bridge on the left of the 2 available connections.

The original card is a Sapphire Toxic 280x and the 2nd card is a MSI Gaming 280x. The toxic is higher spec.

i ran 3dmark extreme and recorded the cards performances.

this is what GPU-Z shows me for the Sapphire:
7p8.png

fq2.png


and for the MSI
g5.png

gfd.png


i'm using Catalyst 14.1 beta and also tried the stable drivers.

it is evident that the Sapphire is doing all the work and the MSI .. well.. isn't.

AMD CrossfireX is enabled in the CCC.

i have a 850W PSU.
i5 4670k @ 4.2ghz
8gig DDR4
MSI G45 - (Supports 16x, 8x8x, 4x4x4)

also as the cards show at different clock speeds, aren't they supposed to
What am i doing wrong?
 
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goodguy713

goodguy713

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Oct 23, 2009
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uninstall and reinstall the AMD drivers with the crossfire link connected to both cards. when running crossfire especially in desktop mode only one card will actually ever be utilized. when gaming you should see them both rev up. I personally think its the fact that you dropped in a replacement with out updating the drivers while the new card is in and connected via crossfire. Its something that tends to happen a lot.

the issue with your cards not showing the proper speed is because the actual bandwidth for the graphics part of your board is set to 16x max but its pci epress 3.0 so if you add another card for crossfire it will automatically drop your graphic card bandwidth to 8 x 8 .. basically it splits it both of those graphic cards should have no issues with band width how ever if you were to add another one I would only consider doing it on a LGA 2011 platform that has more bandwidth
 
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Jonathan Cave

Jonathan Cave

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Oct 17, 2013
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During 3dMark extreme testing, the is an evident problem especially in the last fight video between the two guys it jumps to 30fps then to 7 fps constantly!

the cards are defnitley running at different speeds see the CPUZ memory/gpu speeds at the top. 1020 & 1150 & 1600 & 1500

MSI:
dfd.png

Sapphire:
789.png


3Dmark score:

Capture.jpg


before the 2nd 280x i was getting 4100!

essentially both cards aren't working together (at the same speec) and this is backed up by the jumping in FPS i see which i believe is the bottlenecking of the different speed GPU's

Video of jumping FPS http://www.youtube.com/watch?v=mVSsSKYWr7U&feature=youtu.be
 
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