Quote from: wilkas on October 30, 2017, 05:43:13 AM

Quote from: QuintLeo on October 30, 2017, 03:04:08 AM

PCI-E 6 pin to feed the riser is best.

I dont understand this. The priciest PSU's have only 6x 6+2-pin PCI-E connectors. Do you use two this expensive PSU's to power one rig with 6x GPUs?

I'm not using 750 watt PSUs in my rigs - I'm using 850, and so far only ONE of them is intended to be a "full riser" rig.

Limit of connectors CAN be an issue though - which is why one of my risers on the "pure riser" rig is running on a dual-Molex to PCI-E adapter I had as a left-over from one of my older GPU purchases, and why I'm not buying any more Aorus cards (2 x 8-pin is a PAIN when a lot of PS makers put either a 6+2 and a 6-pin or an 8-pin and a 6-pin on their "dual connector" cables).

Keep in mind I designed that particular rig to run 1080 ti cards, ALL of which have 2 power connections (6+8 for some, 8+8 for the rest) with a minimum of a 250 watt factory default TDP.

3 cards per 850 is MARGINAL if I was running them at 100% TDP, and NOT ENOUGH if I was running 3 cards at 100% AND the rest of the rig on one PS - only reason I can get away with the 850 is that I'm aiming for more like 200-220 watts per 1080ti, and the PS that runs the MB/CPU/RAM/HD will have a pair of 1080ti and something lesser (1080 1070ti or 1070 depending) as the third card.

A lot of my rigs are 3-card "no riser" rigs, left over from my Folding days (where you NEED a lot of bandwidth to fully utilise the cards) - those rigs were usually a pair of 1080 at 180 watts each and a 1070 at 150, or a pair of high wattage 1070s (Gigabyte Windforce or G1 models) instead of 1080s, or a single high-wattage 1080 (Gigabyte Windforce) at 200 and a pair of 1070s "pushed" a bit to 160-170 watts - and they ALL had at least a quad-core CPU in them to keep the cards busy so the base system power draw is rather higher than a "pure mining" rig normally draws.
Those rigs mostly have the CPUs doing BOINC work to earn some Gridcoin, but eventually I'll probably shift them over to Monero mining.
Folding needs a LOT more CPU work and transfers a lot more data to/from the cards, it's not like Mining where the data transfer is small (except ETH/clones during DAG file loadup) and you can get away with using a 1x PCI-E 1.0 connection with little or no impact on your hashrate.