A test im currently doing is on the intervals...

I have 4 Asus Turbo 1080ti's set @ default interval
I have 4 Asus Turbo 1080ti's set @ 600 interval 10 minutes
I have 4 Asus Turbo 1080ti's set @ 6000 interval 1 hour
I have 4 Gigabyte 1080ti's set @ 36000 Interval 6 hour
I have 2 EVGA 1080ti's set @ 3000 interval 30 minutes

I set each one up to a different wallet address on zpool

Currently....
Highest earnings: 3000 interval
Lowest earnings: 36000 interval

Order of earnings: Highest to Lowest for past 23hours
3000
6000
Default
600
36000