As title, which is best. My current rig is basic;
2x 1070
2x 1060 6GB
1x 1080
Some motherboard with 13 pcie slots.
850W EVGA PSU.
850W Cheapo PSU for 1080.

I want to expand and add another EVGA PSU and either
3x 1080ti @£680 = £2040
or
5x 1070ti @£420 = £2100

Has anyone trialled both, which is best!?

Thanks.