Need help on a Crossfire cooling issue

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omega9380

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May 20, 2013
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I'm running dual XFX R9 290x (R9-290X-EDFD) cards on a Gigabyte 990FXA-UD5 Rev 3.0 mobo. The two cards are currently air cooled and slotted in the PCIe 2.0 16x slots on the board. I am planning on upgrading the cooling on these cards using 2 Corsair H55 closed loop coolers and 2 NZXT G12 adapters.

Admittedly not a lot of games take full advantage of Crossfire but so far this setup has taken just about everything I throw at it.

Because of how close the 2 16x slots are on this board (the two cards have MAYBE 3mm space between them) I am planning on moving my secondary card to the 8x slot on the board to allow for better airflow and to accommodate the water block.

My question is, if the secondary card is in an 8x slot, will that downclock the primary card to 8x? Or will it still run at 16x? I know I will suffer a performance hit running the card in an 8x slot, how bad will it be?

The Corsair H55 is 60 bucks, so I'm a little leary about spending the money on 2 of them if I would be better off going with a single card rather than suffering a performance hit in Crossfire mode.

And before anyone suggests getting a new card, I've considered that. Until I searched around. Thanks to the cryptocurrency push, GPU prices are absolutely ridiculous right now. I'll stick with what I have until I get a game that won't play on this setup (which hasn't happened in the 4 years I've had these cards)

Any help will be great. Thanks!!
 
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I think it will run 16/8 and the speed difference is negligible, even if it drops both to 8x.
 
The performance loss is negligible on 16x vs 8x, loss of 1-3 %.

Were you able to get this setup working? I actually cant fit my cards, 290 vapor-x's, to fit on the two 16x slots, ie 1st & 3rd. The card is 1&1/2 lanes wide... I am running the same Mobo as you and can't seem to get my two 290 vapor-x's running on the 16x & 8x slots, ie 1st and 5th slot.

I am also considering going with water blocks but I wanted to be sure I'm not missing something. I may need to try 3rd & 5th slot instead see if that makes a difference.
 
Valor said:
The performance loss is negligible on 16x vs 8x, loss of 1-3 %.

Were you able to get this setup working? I actually cant fit my cards, 290 vapor-x's, to fit on the two 16x slots, ie 1st & 3rd. The card is 1&1/2 lanes wide... I am running the same Mobo as you and can't seem to get my two 290 vapor-x's running on the 16x & 8x slots, ie 1st and 5th slot.

I am also considering going with water blocks but I wanted to be sure I'm not missing something. I may need to try 3rd & 5th slot instead see if that makes a difference.
Click to expand...
Just realized using the 3rd & 5th slot is going to be the same space issue as the 1st & 3rd.
I will try a bridge and see if it will work using the confugurations above. It seems skipping the 3rd lane makes it crash for me.
 
I was running R9-280's on a 3 way SLi a x58 board and I found slot 1 and 3 to be the best setup for heat and load.
 
Valor said:
Just realized using the 3rd & 5th slot is going to be the same space issue as the 1st & 3rd.
I will try a bridge and see if it will work using the confugurations above. It seems skipping the 3rd lane makes it crash for me.
Click to expand...

Seeing this in your user manual.

cf.png
 
Have you considered using a custom cooling option on at least the one of your cards that is the hottest? There are many options out there which would probably improve the thermals dramatically if you want to do a little tinkering.
 
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