Is there a 2x 7990 cooling problem?

[Bonblonc]

I'm considering adding another 7990 into my system as I want to purchase a 4k display.

However, there is some speculation on the internet that there is a fatal cooling problem when two 7990s come together. My case does have good air cooling, so I just don't see it being a problem. Thoughts?

 

[Flashheart]

They will run hot, but undervolting will help this.

Not sure I'd be overclocking with two of them in tandem...

 

[borley]

Couldn't you watercool?

 

[BuzzLloydyear]

I had a bad experience with my single 7990. It runs incredibly hot and it took me a few months before I managed to nail the temps down properly (I obviously got drawn the short straw when I received mine). One of the things I had to do (amongst many painstaking steps) was to remove the Sound Card from my PCI-E slot as it was blocking air to the card. Bare in mind the sound card is far smaller than another 7990.

I wish to move towards 4k myself, but it's absolutely impossible for me to do it with 7990's. Without knowing what cooling is like in an ideal situation, where you have not got a bad card. I could not say specifically whether it would be doable on air, but I certainly wouldn't recommend it from my experience. Under water you would have no problems, but on air, I would be very sceptical.

 

[Kaapstad]

OP don't do it

At normal resolutions dual HD 7990s run very very hot, when you run @4K this makes all cards run even hotter as they spend more time under heavy load.

The other thing to remember is the HD 7990 only has 3gb of VRAM per GPU, this is nowhere enough.

I think if you want to give 4K a go a compromise would be to sell your HD 7990 and buy a couple of 290Ps. You will still have to turn settings down because of lack of GPU grunt and their 4gb of VRAM though better than 3gb will also mean the odd compromise. You will still have to be careful with temps though the 290Ps will be cooler than a pair of HD7990s.

If you go for the 290P option you are still going to need good case air flow with good spacing between the cards.

 

[Woodsta888]

Hi,

I'm running one 7990 at 4K and I was impressed with how one 7990 fairs at 4k. Better than I thought.

The 7990 was never a cool card and some run hotter than others and two in a case will require wind tunnel airflow. They can be cooled with air but at the sacrifice of noise where you'd have to ramp up the case fans when gaming. But if like me you game with a decent set of headphones then noise wont bother you when gaming at full tilt although I guess many fans running at 2000 rpm+ maybe audiable especially if you like you case next to you on your desk (I don't).

The 7990's draw air in the top and dissipate not only from the rear of the card to outside the case but also from the sides of the card - back into the case. If you can give the 7990's more air than they need then I think they can be kept cool but they'd still run in the 80's on air. As Flashheart says - undervolting is key for lower temps and so is supporting the cards due to sag.

If it were me I'd investigate the Quadfire issues that I remember giving problems a while ago where they didnt scale very well. This maybe fixed but this is all I can remember. Tri fire on the other hand with another 7970 did scale well but thi all needs revisiting.

I'd try one 7990 first at 4k then make your extra GPU purchase later - me I'd probably try a 7970 in trifire or sell my beloved 7990 and get one of those x295 x2 deals at £699 - cool and very powerful with 2 290x's pre overclocked

For reference I play BF4 with all settings at max/ultra apart from the following;

Motion Blur Off
AA off or sometimes 2x
Post processing off
FOV 70
SSAO (not HBAO)

I get a solid 60-70fps on 64 player hardcore infantry only servers.