Nvidia cards do not work with PCIe splitters as far as I've seen. If you get a ASUS Prime z170-A or Pro you can probably get 7 cards working, but you'd need to likely have 2 - 850W+ PSU's in order to not fully max them. A single 1500W might work as well, but you'd likely be pushing it.
Make sure you have a 20A breaker on the circuit you use or split between two circuits.
Thanks for that information.
Wyh do you think only 7 cards will work on Asus Z170-A? It has 7 PCIe ports + 2 M.2 slots. The M.2 to PCIe adapter is an "adapter" not a splitter, so at least 8 cards should be possible (i thought). Or am I wrong?
Why the 20A breaker? You mean the thing in the fuse box?
People have struggled getting that many Nvidia cards working simultaneously. You might be able to get 8 working, but it will likely take a lot of fiddling and may not work. Nvidia's draw more power and require more PCI-E resource channels than AMD cards so at least on Windows it tends to complain and although will see the card may not work properly. Look around there are plenty of people who have tried to do what you are doing, but as I've said I haven't seen a lot of luck with more than 6-7 Nvidia cards at once on the same system.
As for the 20A breaker it's because you will get roughly 1800W of total power at 100% load out of a 15Amp breaker.
Assuming you're in the US with standard 120v home power.
Ohm's law = 15 amps x 120 volts = 1,800 watts
You don't want to run at full power otherwise you run the risk of popping the breaker when you have power spikes and such. Circuits can also get hot and cause fires if they are run too close to maximum capacity 24/7. It's just better to be safe than sorry IMO. There have been plenty of stories of people having meltdowns/fires because they didn't pay attention to how much power they were trying to draw, especially on older wiring. Also I presume you will have things like a monitor for setup and potentially fans running for cooling that will likely be on the same circuit. All of those things take more power and even though you may plug them into different outlets most home power circuits will have all the outlets in a room on the same circuit. Most home breakers are only 15A unless you are looking at a utility, laundry, or kitchen.
I've had multiple systems with 11 x NVIDIA 1080 Ti's and 11 x AMD RX 580's running simultaneously without any issues.
