question to those that use 2 gtx

colcurve

Hi, I was hoping to improve my system by adding a second GTX, but the PCI-slots on the motherboard are very close together and the two GTX would sit directly side-by-side, with just a few millimeters apart. My main card is a 980ti, and for testing purpose I added an old 470 (980ti on the bottom and 470 on the top) to see how it goes with the temperatures. And it was not a pleasure, the fan of the 470 was spinning at almost the maximum, 88 degress in the card. It sounded like an airport. While the 470 cards heat up a lot anyway, I assume the main problem is that the fan of the upper card cannot suck in the air efficientIy.

So I wanted to ask whether there is anyone successfully runnig a dual GTX configuration with cards sitting close together, and give some advice. I noticed there are watercooled cards like this one: https://www.evga.com/products/specs/gpu.aspx?pn=16add31d-8463-430a-a2a3-f9f1fd49e9a6   ; using a watercooled element that can leave the heat at a different place, but unfortunately, there is still a classic fan involved. If a hot card is sitting right next to this fan, I wonder if that is a problem leading again to airport noise...

Thanks ;)

 

 

 

 

Ivy

The best solution for me was to get a external graphic amplifier box, I use a older Alienware Graphics amplifier 4 slot gaming box that I put 2 gtx  980ti's in them.  But there are a number of cheaper ones you can get now days , I seen gpu racks at best buy that will hold 8-PCI2 1080ti cards for $120.  you will need to buy a external power supply.

 

outrider42

Does your case have more room for more fans? Many do and you can increase airflow in the case. Also, the 470 is quite old, it may run hot as it is. I did a quick Google search and found people hitting 81 and 82 just playing games, and you are only a bit higher. A more modern card with a good heat sink will do better.

Another thought, some cards have massive heat sinks, and sometimes they are too big. I am betting one or both of your cards are 2.75 slot cards, which would be very tight indeed. You can try to get a card with a good cooler that is smaller. Read reviews on what you are looking for. And of course water cooling is an option, but that's such a big expense.

BTW I have a 1080ti and 970, both 2 slot sizes and on air. The 1080ti gets hotter, which is expected, but it only peaks at 69 and sometimes 70. The 970 somehow stays super cool in the mid 50's even at 100% constant load. My new case has two 200mm fans up front, and I use software to increase their speed. I also use MSI Afterburner to control both GPU's fans. I set an aggressive fan curve. Controlling your fans and having good airflow is super important to keeping temps down.

joseft

Biggest thing here would be your case. Its not just a matter of how many fans the case can hold, but how the air flows through the case and where the fans are situated. Having 10 fans on all sides of your case will not do you any good, the air needs to flow. Intake and exhaust. Cool air in, warm air out.

Then there is the cooler on your cards, the standard coolers that come on the base level cards are not great and tend to result in thermal throttling even under ideal conditions. Most GPU manufacturers do a few different versions of each card, with incremented levels of overclocking and/or better cooling systems on them. 

If you are going to run multiple GPUs, you really want cards with good coolers on them, and a good case that is designed for good air flow. 

I have 3 GPUs in my machine, and two of them are about as big as GPUs come (Titan X with huge triple-fan coolers on them) with another still reasonably large GPU in between them (GTX 770). And temperature most certainly can be an issue, even with a very good case and the good coolers on all 3 cards. I also use MSI afterburner with an agressive fan curve to help with this, but they still easily get to the max temperature that i let them to before thermal throttling. I have removed the gtx 770 from between the two titans to open up a big space between them, and test the effect that has on temps, and with the big gap there and the big coolers on the titans, the temp difference is HUGE. They dont even get to thermal throttling temp. But i kind of need the third GPU in there to drive my displays (4 of them)

When i built this machine, i seriously considered going for a full custom water cooling loop for all GPUs and CPU. But ended up not doing it, due to the added cost and not having much experience building watercooling loops. And i kind of regret it now, because i did have the money to do it back then and i was just being overly frugal. 

Not sure what motherboard you are running, But if you do only have two PCI slots, you are kind of stuck with this problem. Most high end motherboards these days have 3 or 4 pci slots, and they are prioritised and setup in a way that makes it the most beneficial to have the cards spread if not utilising every slot. So you would use slot 1 and slot 3 if running only two cards, instead of slot 1 and 2. Not just for cooling, but for bandwidth too. One of the many reasons its prudent to build a PC with potential future upgrades in mind

 

 

outrider42

Daz Iray has been proven to not care about your pcie bandwidth by Puget. It doesn't matter if you have 8x or 16x or 4x, and thus it doesn't matter which slot you use. Shoot it doesn't even matter if you use pcie 2.0, the cards still rendered the same speed. So pcie bandwidth is not a concern for Iray.

My cards are only about 1 inch apart, so they aren't exactly far from each other. My motherboard only has 2 full slots, and if had to guess, I bet my motherboard is no bigger than the op, ATX is ATX. If my cards were larger, like 2.5 or 2.75 slot designs, they would be just millimeters apart. This proves you don't need a fat GPU cooler, just one that is proven to work well. I very purposely chose the cards I bought for both their thermals and their size. They are only dual fan shrouds.

joseft

outrider42 said:

Daz Iray has been proven to not care about your pcie bandwidth by Puget. It doesn't matter if you have 8x or 16x or 4x, and thus it doesn't matter which slot you use. Shoot it doesn't even matter if you use pcie 2.0, the cards still rendered the same speed. So pcie bandwidth is not a concern for Iray.

 

My cards are only about 1 inch apart, so they aren't exactly far from each other. My motherboard only has 2 full slots, and if had to guess, I bet my motherboard is no bigger than the op, ATX is ATX. If my cards were larger, like 2.5 or 2.75 slot designs, they would be just millimeters apart. This proves you don't need a fat GPU cooler, just one that is proven to work well. I very purposely chose the cards I bought for both their thermals and their size. They are only dual fan shrouds.

I did not intend to imply that pci slot bandwidth was a factor for rendering, i only meant to explain that motherboard manufacters stagger the slot order like that to maximise utility and performance if only 2 of the possible 3 or 4 GPUs are installed. 

Yes, ATX motherboards should all be the same size. But that does not mean they all have only 2 full PCI slots. It depends on the socket type and intended market. Plenty have 3 and if i recall correctly, some of the older generation ones had 4. e-ATX mostly have 4 and even 5, like mine does. 

 

 

kenshaw011267

Most newer ATX have 3 full length slots 2 close enough for an sli setup and then usually the bottom slot, which is frequently a x4 slot.

nickalaman

My Main card is a 1080ti Asus Strix which is a 2 and 1/2 slot card. Once i added a second card, things got really loud, the strix did not leave much room for the cards to breathe, so i just hated it. And once the cards would heat up, they would throttle down. So I kept. the strix on pcie- slot one and bought a pcie 16x riser cable and took the second card out of the box.and put it beside the system. The noise went down dramacticly, it was so good that I decided to add a thrid card on the out side. It's not pretty and i plan on building something for them but for now it works and from my angle i see nothing.

 

 

the3dwizard

I had a similar problem plus I wanted to run more cards for rendering, my setup isn't for running SLI.  I have one 1070 TI in the workstation and I am running three 1070 TI's outside in a milk crate with a 800 wat power supply.  I use PCI-E 16x to 1x Powered Riser Adapter Cards for connecting the cards to the motherboard.  No extra cooling needed since they are outside the workstation.  Works great for rendering in Iray with 4 GPU's.

Cheers!

nicstt

the3dwizard said:

I had a similar problem plus I wanted to run more cards for rendering, my setup isn't for running SLI.  I have one 1070 TI in the workstation and I am running three 1070 TI's outside in a milk crate with a 800 wat power supply.  I use PCI-E 16x to 1x Powered Riser Adapter Cards for connecting the cards to the motherboard.  No extra cooling needed since they are outside the workstation.  Works great for rendering in Iray with 4 GPU's.

Cheers!

never thought of doing this; just ordered some risers

 

Mattymanx

I have two Zotac AMP Extreme 980TIs and the top one will always run hotter then the bottom one.  I have even switched them around as a test and it was the same.