I have a few rigs with 3 or 4 1080ti, they work perfectly. But for rigs with 7x 1080ti, ram usage spikes to 99% within 10s of running the miner, hanging the whole system. Do I need more ram or page size, or is the issue due to something else?

Specs:

7x 1080ti FE at 70% PL
G4560
4GB Ddr4
67gb virtual ram

1600w psu


The other 3/4 1080ti rigs are doing 3.9 - 4.1mh/s each.