Topic: Power supply capable or too small? (Read 156 times)

very true, planned obsolescence is an actual thing in consumer grade kit especially oem stuff. I just had a reminder of that combined with a scam cheap ebay china style 2000W "on the label" psu that appeared to basically be a fan modded 1000W psu and at 1200W draw it was screaming its nuts off so not going to last very long tho it worked lol. That psu has been returned as of today lol and not doing that again...... proper brands for me moving forward.....

A mining rig always consist of 4 GPUs minimum so I don't think a 550watt power supply is a good call, even if you can lower voltage on a particular algorithm today what if the present coin you mining isn't profitable anymore? And tomorrow you just switch to another without knowing how power consuming the algorithm is? Your PSU will go up in flames so the safest PSU for a mining rig starts with 750watts minimum

Here is my experience with those cheap PSUs that usually come in a generic silver aluminum looking box. They might say 450-550Watts or so, however you need to see how much current each rail can supply. Because back in the early 2000's, there wasn't as much need for +12V but there was more for the 3.3V or 5V (can't remember) and you will find that. Even though its 550Watts, the usuable +12V is only maybe 250 Watts or so.

Even if its higher, if you run it 24/7, I gaurantee you, you will kill that PSU. I learn't this the hard way back in 2014 when I started mining. I was cheap and instead of paying $75 for a quality PSU, I bought a few of these second hand for $5-10. They were all like 400-500 Watts. And if you run it more than 50% load, you will kill that PSU within a week or month.

I think they are more geared towards people who NEVER game on them and just use the desktop for minor browsing.

Do regularly blow the dust from the inside of the PSU with compressed air as just like your cpu cooler the chips inside the PSU have heatsinks that lose cooling efficiency as dust builds upon them which makes your psu hotter and with matter to burn in the form of dust = fire.

I hope you also understand that PSU is different from PSU? I'm guessing that those PSU in your PC are OEM brands? That's a red flag mate don't use them for mining if my point is correct, just because they wrote 550watt on the PSU doesn't mean it will deliver that exact amount, better go for strong PSUs like Corsair, OCZ and others, don't use OEM PSU

It depends on the PSU quality really, if you have a good brand with 80+ GOLD tag, then yes, the actual watt will be not that far from 550W (or ~478.5W). BUT if you use stock (casing PSU) with an unknown brand, the chance is, probably it will have less than 60% efficiency. It means your real PSU power would be ~330W. So the answer is, yes, if you have good quality PSU.

100% follow this advice! This is spot on. In general, I would recommend buying something like a Kill-a-watt monitor to plug your systems into at the outlet that way you know exactly how much power you are drawing from your systems. In general you always want to stay under 80% of the max wattage for the PSU or for the breaker in general. Following those rules you will keep your components safe along with your home.

In order to avoid costly hardware failure and even fire it is best imo to build your rig with a power supply that meets the power requirments of the GPU's running at stock volts and overclocked so whatever they draw power wise when running flat out molten hot should be your calculation spec

Any error or gremlin in your rigs operating system or drivers might one day without warning invalidate any software applied under volt meaning your rig draws more power than its cheap maxxed out power supply can handle and especially dangerous if it does this in your absence for a good while.
(for me 6 x rx6800 = 300 watts =1800W plus some for effeciency power conversion takes it upto 2000W and that does not include system overhead so add another 200W for that, in reality by software under volt my GPU power consumption is half because 6 x 150W =950W but if that setting was nullified oh dear big trouble ahead if using single cheap 2000W psu).


There is also a risk thats highly likely of premature PSU failure by running close or even over its power rating constantly so avoid stressing your kit and build in some redundancy for safety and longevity. The power conversion efficiency of a Power supply will never be 100% and even 95% claims are worth questioning imo. If you have a 500W PSU it will give a safe 450W out but not all of that is on the 12V rail so proceed accordingly with long term safety and reliability of power supply in mind. More is better to avoid so for this setup 750W would be preferable.

For eg i just bought a psu claiming to be 2000W 95% platinum 8 gpu capable. yet with four GPU attached underclocked each drawing 150W the psu fan was full speed making a racket pumping out lots of heat like an electric heater and it was only pulling in at the wall socket 800W max. This psu has a label on it that i dont trust and its getting returned as unsuitable as i no way trust it to run at its claimed label rating and even if id id its to noisey, This psu is the same size and weight as a 1000W maybe with a fan mod so it can be driven harder than its rating and i dont like it im not leaving it unattended in my home knowing anyone can print a label off, right.

so back to 2 x 1000W for my 6 gpu rig and less noise n risk of fire and those paying attention should be able to point out even 2 x 1000W is slightly to low for the needs of my example if they do draw 300W max but these GPU actually run at stock volts around 240W so its 240W x 6 = 1440W + 200 for system overhead = 1640W drawn from two 1000W psu gives safe spare capacity to accommodate power conversion efficiency so as not to stress them or the rig. Also consider in time that electrical components age and reduce performance accordingly = fire.

2*rx580 =300W
1PC 100w
Total 400W
If your PSU costs $ 30-40, then it is not designed for such a load.
550 watts can be written on a cheap power supply, but the maximum is designed for a maximum of 350-400 watts, and then there will be overheating and a decrease in control voltages.

Yup you can add one each of them, just one hahaha, but not doing any over voltage if you doing overclok, in constant running for mining, your psu will die shortly maybe 1-2years

Adding more GPU means your PC aren't for gaming anymore but why not just add all cards on a motherboard for mining and use the second for other things like learning? A single motherboard can take up to four graphic cards even if it's OEM motherboards, this will even draw less watts instead of using two motherboards for mining

Yes no problem 2 cards. You can run 3 cards on a  550w power supply if you downclock and undervolt this cards.

If I were you OP I would install all four graphic cards on a single motherboard and use double power supply on the motherboard, this way you will have enough power 1100watt enough to run more than four rx580, all you need is add2psu, do research on that

I don't think it's necessary

You will max out the power supply because a rx580 draws 140watt from wall and two of that is almost 300watt, even if your CPU and motherboard can manage 200watt the power supply won't live that long, use Nicehash and it's low power mode in mining dashboard, this will shrink the rx580 power consumption down to 80watt and 100watt from wall

I wouldn't do it especially if it depends on undervolting and choosing a low power algo. There are other variables
like what else is the PSU powerring. You said they are desktops not mining rigs. Do they have a big CPU? water cooler?
optical drive? hard drives? There's also the quality and 80+ rating of the PSU to consider. If you push it you will likely
have instability even if it doesn't crash as soon as fire up a miner.

If you undervolt the cards and they can only consume like 90-100 watt each and don't use them for gaming but for mining yes it would work as I had once with a Corsair running two Gtx 1060 which would consume near the same amount of energy as Rx 580 undervolted and I mined with them.Also do not mine RVN as it consumes more electricity and it may or may not work but for Ethereum I think it will work,always with undervolted cards.

Also make sure your PSU has 2 x 8 pin connectors to support 2 GPU-s as one Rx 580 needs a 8 pin connector.

I have two desktop PCs with a single rx580 in each and I'm thinking of adding extra rx580 to both desktops but the desktops has 550watt power supply each, can extra rx580 works in both PC?