What happens if I corssfire in 16X and 8x connectors

[rasinita]

I got a Maximus Extreme motherboard and 2 HD4850 cards (also from Asus). It seems like the 2 16X pcie slots are too close to one another to crossfire with stock cooling. Top card goes to 80 degrees in idle. Since the top card heats up like hell i decided to get a vortex akasa cooler for it. Didn't manage to fix the temperature issue as the top card still heats up to 90 after 3 min of gameplay and the cooler from the top card now touches the bottom card. I've got another 8x pcie slot with a 16x connector that is further away from the 16x connectors and i was thinking of plugging the second card in there. Is it possible to crossfire like that. And if it is will i lose performance overall or see an increase?

And if anyone has any suggestions about how i can crossfire with the slots that close to one another please tell me.

 

[huron]

Really?

I believe the 4850s are single slot coolers and all PCIE slots are at least 1 slot away from each other.

I know the cards run hot, but they should fit side by side. I do think they will be like a furnace in there, but they should fit.

You can crossfire with a x8 slot, but it will be a slight performance decrease (most benchmarks I have seen show only a few percentage points).

You may want to check your motheboard manual about doing that.

 

[rasinita]

Well with the stock coolers they weren't touching but after i fitted the akasa vortex neo on the top one the fan from it was spinning on the bottom card. I had to put a piece of rubber between them to keep them apart.
The thing is there is very little space between them and while the temperatures were fine when testing each separately when in crossfire mode its 80 degreees idle for the top card and normal temps for the bottom one. There's like 10-15 centimeters of space under the bottom one but 5 mm under the top one. I fitted the akasa as i figured it will blow the heat out the back of the case and ill solve it. Im having the exact same problem still. 90 degrees after 3min of gameplay...

About crossfiring with a 16x and a 8x slot ... will i see a performance increase compared to just using 1 card in a 16x slot?

 

[huron]

You will see a performance increase, even with one of them in a x8 slot.

Those cards do run hot anyway. Sorry you went through so much trouble to get them crammed in there.

Good luck with your solution.