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Hello, guys
I'm kind of stuck here.
I have a 4 GPU build: 3*1070 + 1*1060 + PSU Corsair RM750 (4*6+2 pin)
Would it be right just to connect only GPUs directly from PSU to the 8 pin connector on the card without powering risers?
Is PSU power would be enough for that build?
Thank you

still, need power because Riser needs power max 75W both Molex or 6 pins.


Every time I want to build a Rig, I always calculate a standard GPU that needs Powering because my rig is stable and rarely problematic. (Yes, I know if doing it with undervolt total powering is not same.)

This's safer calculate.

1070 has a TDP of 150 W x 3 = 450 W
1060 has a TDP of 120 W x 1 = 120 W
total = GPU requires 570 Watt power then 750 W - 570 w = 180 W remaining power. Not to mention SSD, RAM, RISER  that has not been calculated yet.

So 750 W, not enough

get a platin or titan rated 1200 watts psu, it will save you alot of electricity costs if you dont run psu at full load

Slot draw (riser) is included in the card's TDP. The motherboard and the CPU draw less than 50 watts, not to say 20.
Most GPUs are heavily undervolted and draw about 60-80% of their rated TDP.

750W is perfectly enough for these cards. It will run at about 600W on stock load and 450-500W when undervolted.

I totally disagree. I have a set of 3x570 + 1x1060 mining Eth taking 500W from the wall. Of course I undervolt them otherwise it would be close to 600Watts. So its clearly ok to have a 750 PSU for those cards (1070 are close to 570 in terms of consumption) provided that it is a good one.

Yes, that's why I use safer calculated, also with how much power that motherboards needed.

I never use software calculation about power consumption, it will give more gap between what shown on a software and the real (at Wall), trust me.

I always calculate max power draw for each part.

yeah, but I never found even at old computer that has 100 Watt PSU. It's called safer.

but isn't safe and will kill your cards slowly

NVIDIA's power draw is extremely precise, within milliwatts. You don't calculate the power draw from the wall because the power supply has losses when converting AC to DC. The ratings on any decent PSU are on the DC side and in this case are perfectly enough for ~60-70% load. The PSU can handle it even at 100% load, just not so efficiently.

So no, a decent PSU won't kill your cards, only the cheap chinese knockoffs. OP has one of the best PSUs available.

750w PSU not enough, maybe i can use 850w PSU
3x1070 (min load 400w, max load about 600w)
1060 (min load about 70w, max load about 120w)

No matter what, in mining industries, GPUs is our asset. so we need to make sure our asset always in good condition if we plan for along term. if we truly calculate OPs HW, I think power draw would be around 650-700 Watt on a default setting.

it's mining we need to run our Rig 24/7. So, I guarantee only using more power space would keep our asset safer. Hashrate per Watt is important, but the most important thing is to make sure our Cards has enough power.

Talking averages if you undervolt your cards.. 120 for the system, 80 for the 1060, 120 for the 1070’s. You would be right around 75% power on a 750w which is fine. But hard to say because some people run their cards at higher than 80% power.

I would go 850 for the extra head room and if you want to add another card you can. Or you can buy another 850 and get up to 8 cards. More options available.

guys, appreciate your insight with this!

what about PCIe connectors?
I would need minimum 6 *8 Pin PCIe connectors from the PSU for 4 GPUs plus 4 risers: 4 of them would power 4 GPUs (150W each), 2 of them would power 4 risers, using 8 Pin Male to Dual 6 pin Female (2*150/4=75W for each riser).
Correct?

So you are planning on using Y splitter 8 to 2x6 pin, it's enough to power your riser. But your PSU only has 4 PCIe 8 pin, right? You could use a riser with a Molex connector, so you can powering your riser directly from PSU using Molex connector or else use 6 pin riser with Molex to 6 pin power. Will safer than using SATA connectors.