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

Removing the backplate of card 2 would definitely work.

Is it totally safe to do this? 
 

Sajin
Removing the backplate of card 2 would definitely work.

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. 
 
 
 
 
 

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.

Round rubber sink washer or 2 would work between cards to prevent sag.

Sure one could find those at any hardware store.

Good job!

likeshesaid
Okay so spacing AND heat issues are now resolved! 
 
Here is what I did:
 
1. Take backplate off of second GPU in stack:


 
2. Use putty from backplate of GPU2 to keep washer in place on the backplate of GPU2: 



 
3. Make sure washer is in a good spot (good contact) with GPU1 and NOT in a weird spot (hitting fan or not contacting the front casing well):


 
If I made any oversight here please let me know. I know thermal putty is conductive, correct? However, I assumed that since it will be on the rubber washer, it will allow the board components to still function well but won't have any contact issues with the top card. 
 
I'm hoping this works well! Seems pretty good so far! Let me know and thank you so much everyone :) 
 

The thermal tape is not conductive. I've also used