Identical 1080ti rigs, different performance

[david987]

They all have the same: Hardware, OS (Win 10), BIOS version and settings, nvidia drivers, risers, miner & arguments.
The only difference I found between them is that in the low performing one, GPU-Z shows 3.3GB under 'Memory usage (dedicated)' vs 480MB on the high performance ones. Virtual Memory is set to 35gb on all.
There's a 5-10% difference in performance, doesn't matter which algo or miner is used.

Not sure where else to look.

[treespace]

If it's between just two 1080ti's 5-10% could be within the natural variance between particularly good/bad chips.

Another factor could be as simple as temperature.  Depending where you put the rigs one might have better cooling (i.e. on a cold window sill vs in a closet.)

[david987]

It's 6x1080ti rigs, they're all the same cards. Swapped some of them out to confirm it's not the cards.
Funnily enough the rig with lower performance runs around 5-6 degrees cooler per card (better airflow)

Another difference I found is that the memory commit size is 22.4GB/38GB, vs 5GB in the other rigs.