Hello! 
 
I just built a new computer. I have 3x 1080tis (2x SC2's, 1x SC) for rendering. My motherboard has 4x PCIe slots. The way they need to be filled is Slot 1, Slot 2, and Slot 4. Right now I am having issues where Slot 1 GPU's fans are hitting the back of the GPU in Slot 2. I put a temporary hard plastic spacer that separates the ends of the very slightly and fixes the issues. However, I would like a more permanent solution, whether it's a more permanent spacer or something else (I read removing the back of GPU 2 might help???) 
 
Anyway, please help! I have this machine for rendering and don't want to have to worry about this issue in the future.
 
Thank you!!!
Nicole

the cards should not touch ...the gap between cards in small but it should be there
 
maybe the spacing on your case is off ?
 
When you loosen the bracket screws that secure the GPU to the case .. is their any adjustment ? 
 
I've used a 3-way SLI bridge to help align the cards, during install
 
Next thing I'd check is the MB position .. loosen those mounting screws, but leave them in place ... any adjustment ?
 
 
These are different cards ... but shows just how tight the three cards were for me
 

Removing the backplate of card 2 would definitely work.

Hmm, okay I'll try to reposition a bit, although I did this yesterday to no avail. I might switch the top and bottom cards to see if that somehow works. I just did some stress tests and the top card is running extremely hot too (85-90C under full load). Making me pretty nervous. I'll flip them around and see if this helps and also check the case/mobo. 
 
Just a note, I had this issue with my last case too. I also have 7 fans in there plus the 3 fans of my AIO cooler for my CPU. Really surprised at how hot it's running. 
 

Cool GTX
the cards should not touch ...the gap between cards in small but it should be there
 
maybe the spacing on your case is off ?
 
When you loosen the bracket screws that secure the GPU to the case .. is their any adjustment ? 
 
I've used a 3-way SLI bridge to help align the cards, during install
 
Next thing I'd check is the MB position .. loosen those mounting screws, but leave them in place ... any adjustment ?
 
 
These are different cards ... but shows just how tight the three cards were for me
 

Is it totally safe to do this? 
 

Sajin
Removing the backplate of card 2 would definitely work.

I had two Titan XP & 1 - EVGA 1080 FE in that photo - testing before the water blocks ... the stock coolers are "blower style" ... the advantage - blows heat out of the case
 
your SC push most of the heat out of the side of card & into the case ... airflow is an issue ... open side of your case - if temps drop you need to get better airflow
 
 

Dense packing of cards for rendering, deep-learning, or other HPC really calls for blower cards. They pull in air from the squirrel cage blower and exhaust it out the back. Usually, these cards are designed without a backplate and with some recess around the blower inlet. Particularly, look at Quadro cards.
 
However, I have a thread on the EVGA 2080ti blower - which is a fine card, but I had to remove the backplate in order to put them in dense side-by-side. The backplate is not simple to remove on that particular card. Most are, but not that one. 
 
The fan type cards are not suitable for dense installation. They're usually thick, have backplates and exhaust heat down and up into the case, rather than out. So, when dense, one card is drawing in the heat of the other cards, and it will be starved for airflow due to the small gap. 
 
I have several GPU workstations, some are extended and have 7 slots and can handle 4 full-size GPU in dense packing. The others accommodate 2x GPU but only in side-by-side 2-slot spacing. They need blower style cards with no backplates. No way around that, except for liquid cooling. 
 
 
 
 
 

likeshesaid
Is it totally safe to do this? 
 

Sajin
Removing the backplate of card 2 would definitely work.

Yes.

Removing the backplate solved my problem. Thanks! I was wondering if anyone had a recommendation of some sort of spacer I could put in between the cards in case the top one starts to sag. I don't want to have an issue where the top card's fan hits the back of the second card that now has no back plate. There is clearance now but just trying to be precautious. What would work? Rubber, metal? Any suggestions would be great.
 

Sajin

likeshesaid
Is it totally safe to do this? 
 

Sajin
Removing the backplate of card 2 would definitely work.

Yes.

likeshesaid
Removing the backplate solved my problem. Thanks! I was wondering if anyone had a recommendation of some sort of spacer I could put in between the cards in case the top one starts to sag. I don't want to have an issue where the top card's fan hits the back of the second card that now has no back plate. There is clearance now but just trying to be precautious. What would work? Rubber, metal? Any suggestions would be great.
 

Sajin

likeshesaid
Is it totally safe to do this? 

Sajin
Removing the backplate of card 2 would definitely work.

Yes.

When I used to run 3-way SLI, I made little square spacers out of folded electrical tape. Thats what I used to keep a 1/4" gap between the GPU's and it distributed the load a bit. Some go as far as to use the tapped hole in the end of the GPU to attach a support to the case bottom. That was with those gigantic 2.5 and 3 slot  coolers though.