Hey guys,

I have built a rig that is giving me some trouble. The rig consists of the following parts:

1200w Platinum PSU
3x - 5x 1080 TI Sea Hawk X (this one: https://www.msi.com/Graphics-card/GeForce-GTX-1080-Ti-SEA-HAWK-X.html#hero-overview)
5x Powered Risers PCIe X1
H270 M3 Gaming
Celeron 2.8 GHZ Dual
4GB RAM DDR4
60 GB SSD

EWBF 03.4.b solving equihash

Afterburner: 75% power, around +170 Core and +780 MEM but stable for 3 cards (these are watercooled after all). 3 cards have Micron Memory, i have not yet checked the other 2 but they also handle these settings so far.

Issue 1:

Observation after 6 weeks: When running the rig with 3 TIs the rig tends to be unstable: After booting, occasionally Windows does not recognize all 3 GPUs, other times the mining program does not recognize all 3 GPUs. On average, around 40% of starts are successfull as in "Windows and miner recognize 3 GPUS". The CPU usage is around 50% at all times, 45% goes straight to afterburner. Once running it works like a charm and is stable, longest run until i restarted manually was 10 days 24/7.

Is there something at fault here? Am i short on CPU, RAM or hard drive?

Issue 2:
Oberservation after 1 day: I tried to run 5 TIs, then 4 TIs, but the PSU is just not strong enough. In theory it should be as i am undervolting the cards to 190w and the usage 5 cards should be less than 1200w (3 cards run below 700w). I have accepted that the TIs "pull hard" in the first split second of mining, leading to the PSU just surrendering, therefore i have ordered another 1200w PSU (exactly the same model). All 5 cards work and all PCIe slots and risers work until i run more than 3 GPUs at once.

Are there any known limitations of running more than 3 or more than 4 TIs on a rig with my specs? Do i need more CPU Speed, RAM or another Mobo? If needed i will order new parts, just want to make sure that my rig "should run" with 5 1080 TIs and 2x 1200w.

Thank you very much for your help, it is much appreciated!