It's not even just about the slots, it's about the PCIe lanes (which is something I never had to worry until now, though I built countless PCs in the past).
We tried bunch of setups with Threadrippers and EPYC, at the end settled for the ROMED8-2T which is a monster motherboard.
We run 4x 2080s on threadripper systems. What sort of trouble did you run into? I thought threadripper has plenty of PCIe lanes. We didn't have any trouble but it could be I missed something, we had to get it working quick and I didn't do very much benchmarking.
Threadrippers are great and I had 4x Threadripper setup for the longest time, but they are a bit more expensive.
The advantage of EPYC is that because it's so common, we can find used cheaper ones on ebay. They are a bit slower I believe, but we can deal with that by using Nvidia's DALI and decoding images on the GPU rather than CPU.
Ohh I hadn't thought of there being cheaper ones on ebay. That's a good tip, I'll check it out for our next upgrade.
We're doing photogrammetry not machine learning, running some blackbox software that scaled best with clock speed so threadrippers were the most efficient option.
I put them in 4U supermicro boxes with a noctua cooler with 2 9000RPM delta fans attached to it with rip ties.
We tried bunch of setups with Threadrippers and EPYC, at the end settled for the ROMED8-2T which is a monster motherboard.