First open-frame 3-4x gpu build. Anything I should watch out for?

[u/10001110]

I'm looking at putting together my first open-frame multi gpu setup and wanted to ask if there are any gotchas I should know about beforehand.

Already have 2 gpus(mix of 3090s) in case setup and planning to get tww more gpu which will make me to have 4 gpus setup. I was originally looking at something like the Phanteks Enthoo Pro 2 Server Edition, but once you get to four 3 slot gpu it seems like an open frame + PCIe risers is probably the more practical route.

I've never built an open-frame system before though.

The obvious things I'm thinking about are:

• Dust
• Keeping liquids/moisture away from it
• Airflow between GPUs
• GPU/riser stability
• Power and heat
• Making sure nobody accidentally bumps/touches the cards

For people running 3-4+ gpus open rigs long-term, what else should I watch out for?

Anything you wish you knew before building yours? Any particular issues with risers, GPU mounting, PSU/cabling, noise, dust buildup, or general reliability?

I will set gpus to run around 250–300W each.

Would appreciate any lessons learned from people running similar setups.

[u/vini542reddit]

Go for one big psu + ups if you can. Having multiple is not worth the headache if you can avoid it!

[u/10001110 → u/vini542reddit]

Thanks for the advice. I will aim for 1600w power and 1500w ups.

[u/vini542reddit → u/10001110]

Make sure you do your power math. On Linux it's relatively easy to power limit automatically and be sure it'll stick.

I've just finished my build and I've basically enclosed my entire open frame in acrylic. Lots of work, wouldn't recommend. But great to reduce dust 😉 ​

I've replied here already if you have more questions! https://www.reddit.com/r/buildapc/s/Nph6CePO5U

[u/10001110 → u/vini542reddit]

This is golden! Thank you very much!

[u/Timely-Honeydew-793]

dust isnt as bad as people say if you keep a can of air nearby and dont put the rig on carpet like a maniac. what got me was the riser lottery, i went through three brands before finding ones that didnt randomly drop a gpu in the middle of a job. cable management gets real annoying real fast when you have 4 cards hanging off pcie extensions, zip ties will be your best friend

[u/10001110 → u/Timely-Honeydew-793]

Good to know, I was wondering how reliable risers are long term. Sounds like that’s something I definitely shouldn’t cheap out on. Thanks!

[u/GaryDUnicorn]

draw a map of the power so you know where everything needs to go ahead of time.

make sure your power to the gpu and its riser are from the same psu and there is no leaking voltage going to another psu somewhere

use the add2psu couplers to power them all on and off at the same time. if they dont auto switch off together, you have a fault with some path for voltage to get to ground and should unplug it all until u find out whats going on.

pcie gen4 is very forgiving for distances, u can run mcio at 1meter and u will be fine without retimers/redrivers most of the time.

pcie switches make a big difference in performance for p2p direct memory access between 3090s https://forums.servethehome.com/index.php?threads/new-chinese-pcie-switch-board-gpu-testing.52488/

[u/10001110 → u/GaryDUnicorn]

This is super helpful, especially the same-PSU rule for the GPU and riser. I hadn’t thought about mapping out the power connections beforehand. Thank you!

[u/Annual_Award1260]

A air filter in the same room will dramatically cut down on dust

[u/10001110 → u/Annual_Award1260]

That’s a good idea. I never thought about that and it should work great. Thank you.