Topic: How many GPUs can a 750w PSU power? (Read 199 times)

Get a watt meter first and plug in those Vega GPUs first and mine with them then record down how much these two cards are actually taking from the wall, then add a GPU and do the same thing, just make sure you are using 80% of the power supply, let's say 600watt at your disposal

Just ensure you know exactly how much you are using for the entire system as a whole first. Then ensure you are never going past 80% of the power supply maximum to ensure you are operating everything safely. I would advise buying something like  Kill-a-watt to monitor how much power you are pulling, especially if you are at or over the 80% level. The last thing you want to do is fry your equipment or start a fire. When in doubt just get another power supply.

Probably because most people only use 1 video card in their PC, and 2 8-pin connectors are enough.
Miners rarely use such blocks for mining, because it is better to buy a good 850 watt power supply, which already has 6 8-pin connectors.

You better ask why the manufacturers of these power supplies make 2 power connectors for the processor?

The issue with some PSU that are usually <750 watt is that there might only be 2 PCIe connectors and if your GPUs require 2x each then it won’t work. I have no idea why some PSU companies do this. They make a large capacity PSU but don’t include enough connectors to even come close to max of the PSU.

I had PSU like this in the past and basically what I had to do was take the aux CPU connector and repin it to make another PCIe 8 pin plug and used some of the other unused molex wires to supply more power.

A plus bronze 80% efficiency doesn't mean it will output only 80% of your total power.
A PSU rate of 750W will output 750W, not a single less. 80% power efficiency meaning it will waste power input to archive that 750W total load. Tho people want to leave some leech way and don't want to run a PSU 100% of its total output 24/7 as it will degrade the PSU very fast.
Also, CPU, RAM or other stuff doesn't eat all that 200W. A good combo to keep a mining rig stay afloat require much less than that, below 100W peak. I would stay his safety margin to run is below 600W for at least 2 of his GPUs.

Better to use one power supply. The more power supplies, the more power losses, but they are not so big. This is the efficiency and cooling of each power supply.
For example, if you need a 1500 watt power supply and you do not want to use a server power supply, then it is better to buy 2 power supplies of 850 watt each, because it is cheaper.

Yea two power supplies will work either with this add2psu or paper clip method but I am curious about the power consumption, will using two power supply draw same energy as using one power supply? Would using two draw more power?

The good point about PS connectors. As more watts you have as more connectors will be. You can also use 2 PSU's using this thing https://www.amazon.com/Connector-Power-Supply-Adapter-Relay/dp/B07Z84VCFN
Have 2 of these. Working like a charm 

If this power supply has only 2 connectors 6 (8 pins), then you can only connect 2 video cards, which have 1 power connector 8 pins. Vega video cards have a 6 + 8 pin power connector.
If your block has 4 connectors 6 (8 pins), then it will be enough for two Vega video cards and a motherboard.

🤔 I think low power consumption GPUs will be a better combination with those Rx Vega 56 you own, I'm think of graphic cards like 1660 that draws 54watts to 60watts, the new AMD 6600XT is a good one too

Two Vega 56 = 300watt from wall
Two 1660 = 140watt from wall

That's 440watts, you have enough power for MOBO

It depends which gpu's will you use.
One of the best power vs hashrate gpu for eth is AMD 6600. It gives around 31 - 32 mh/s with 55-60W only.
AMD 6700 gives 42 mh/s with 90-95W.
Nvidia 3070 - 60-62 mh/s with 120-130W

All this info is if you mine ETH.
For other coins the hashrate will be different

A 750W psu if 90% efficient at 100% capacity will output 675W and not all of that is 12v.

If your system (CPU, RAM, Peripherals) consume say 200W that leaves 475W split into two GPU's = 237.5W each maximum. Therefore in theory it would be possible to run 2 x Vega 56 @ 210 Watts each however very close to the limit of the psu safe operation limit but absolutely only one Vega 64 ether air cooled or water.

If you look at the power supply strings it will likely have only two strings for PCIe 8 pin power and that should be a clue enough.... If you want to run the 2 x vega 56 on it you will need adapters to convert molex or sata to 8 pin pcie power but be careful to use quality two molex/sata splitter to one pcie 8 pin plug making sure you have two strings for split into one pcie plug so you will need 4 seperate strings of sata/molex for safe operation to ensure adequate capacity of wires for the current draw otherwise plugs n sockets will start melting if they carry to much current = fire, smoke, general bad day. Bear in mind with the two Vega 56 on this psu your at the limit so proceed carefully and think about investing in a better psu a 1000W would be better and give 4 x pcie 8 pin sockets that you will need for 2 x GPU and some even give 6 pcie 8 pin strings so 3 x V56 GPU on a 1000W psu would be possible or just the two V64 if thats what you have.

Play safe.

I have a 750watt PSU and two Rx Vega GPUs I want to know how many graphic cards I can use this 750watt PSU to power, this PSU is a 80 Plus bronze OCZ technology, pls reply