I'll sure you'll agree with me when I say that choosing the right PSU for crypto mining can be a daunting task.
It turns out a server PSU is by far the smartest choice if you want to best bang for the buck whilst making sure your getting the most energy efficient hardware.
In this article, you'll learn what is the most energy efficient server PSU for mining that has a ridiculously low cost compared to the desktop cousin.
As an added bonus I'll lead you through the steps of making sure you choose the right server PSU and all the required cables and kit to get it powering your GPUs.
You'll have a complete shopping list on what's required to make your mining highly efficient at a low cost.
The case for server PSU for crypto mining
I'm comfortable with server hardware and that's because I've worked with it for many years but I'm totally aware that not everyone is - hence I've written this article.
One of the best pieces of advice I was given when I started working with servers was priceless and has given me the confidence to work with many servers over the years. I will impart this to you to now.
"A server is just like a normal desktop computer but it has more redundancy built in. Where a normal desktop has one PSU, as the server will have two, same with disks, CPUs etc."
You'll be mining 24/7
With that logic now in your head lets dive into the world of server PSUs. They've been specifically designed and manufactured for use in environments where there always on. 24/7, 365 days a year. Server PSUs are on all the time and that's exactly what we want from our crypto mining rig. The less downtime the better.
Not only have server PSU's been designed for always on, they are usually more energy efficient than their desktop cousin. This is always a hidden cost when it comes to crypto mining. How much will the electric bill be? Well, let's just say it will be a lot less with the correct server PSU.
The third and final benefit to using a server power supply unit (PSU) in your crypto mining rig is the fact that aftermarket server PSUs are far cheaper to pick up and in supply on many websites. You'd have a hard time finding a platinum rated 1000 watt desktop PSU at under $200 (£175) in today's market.
Why platinum PSUs are the right choice
PSUs are rated by efficiency. Back in 2004 Ecos Consulting, came up with the 80 Plus rating which is voluntary but which most major manufacturers follow.
It goes a little something like this:
Efficient PSU = lower electric bill.
If you look closely at the chart you'll spot that there really is not much difference between the platinum and titanium rated PSU's on paper. In reality, the real difference is cost. Hence the reason we need to be shopping for a platinum rated PSU.
HP servers PSUs seem to win.
The two major manufacturers of servers to date are HP & Dell. I believe HP has somewhat of a lead in the mining community though as all the breakout boards and accessories I can find are all designed for HP PSUs.
So we are looking for a HP platinum rated server PSU.
Wattage consideration & future capacity
This is probably one of the most important factors when choosing a PSU. Yes, efficiency does matter and will impact your profitability when mining but making sure you have ample wattage to power your GPUs is crucial.
The main reason for this is that if you choose an underpowered PSU there's a good chance you'll blow your GPUs which is not a good situation to be in. Especially if you're investing in something like 6 1080ti's. That's a lot of money and you don't want to see it literally go up in smoke.
Again some common sense comes into play. Let's say for example I have two 1080ti's that I want to run on my mining rig. A quick google search suggests that the average wattage for a 1080ti is around 250 watts.
If you can get somewhat more granular with your research. Include the model & make of your graphics card as this can sometimes have an impact on power draw.
The other consideration is if you plan to add more GPU's in future. Our 2 GPU set up will happily run off something like a 750watt PSU. However, if I add another 1080ti into the mix that brings the power draw up to 750watts (250watts x 3). Even though my PSU is rated at 750watts I don't actually get a 750watts draw from it - more like 600 watts. That's down to our energy efficiency. If we've got a platinum PSU rated at 750watt then that's around 90% efficiency taking the real wattage down to 660 watts in the real world.
RULE OF THUMB
The rule here is always aimed higher by a good margin. You don't need to do overkill but be conservative with your calculations rule of thumb I tack on 25%. So for a 750watt setup, I'd add another 150watts which brings me up to just under 1000watt. In this case, I'd choose a 1000watt PSU for my 3 GPUs.
Just remember that if you plan for expansion going up to 6 GPUs then it might be worth just going all in with a 2400 watt server PSU.
The other option is to purchase multiple PSU's. This is something I did with my first mining rig. 2 x 750 watt HP server PSUs and a standard desktop PSU to power the motherboard. You can't mix the power though. What I mean by that is that never use more than 1 PSU to power a device.
A simple rule of thumb that will save you from frying your GPUs, motherboard or anything else.
How to power the motherboard
After watching multiple youtube videos like the one below it seems to be a common practice of using a PICO PSU to power the motherboard.
The PICO PSUs are often used for in-car PCs and run on minimum power - which makes sense as they, in reality, will only be powering a motherboard, Celeron CPU and one stick of RAM in the classic mining rig setup.
No to PICO
This is a great solution which I've yet to try. The main reason I've avoided this is that firstly getting hold of a PICO PSU that has a PCIe power connector looks to be impossible at the moment due to all the mining rigs being built. I could probably wire a PCIe connector to the power in but I really don't want to risk anything to do with electrics and play it safe 100% of the time. That's because my mining rigs run in my house which I don't really want to risk burning down.
The 2nd reason I've avoided this is due to my concerns about power draw from the PICO PSU's. If they are constantly on then a proper PSU is got to be the way to go. I just don't see a PICO PSU lasting in a 24/7 always-on environment. They are designed for cars.
What's the solution?
Simple - a low wattage desktop PSU with high efficiency. The best thing about this solution is that you don't have to mess with cables and adaptors for the CPU power socket and motherboard power socket. A standard desktop PSU has these built in. I use the desktop PSU only to power the motherboard items. No GPUs are plugged into this PSU. Remember what we said, don't power the same device with more than 1 PSU - that's just asking for trouble with slightly differing voltages.
The other reason we only power the motherboard with this PSU is that fact it's low wattage (400 or lower) and will realistically not be able to power a high-end GPU for mining, CPU, and mobo.
Breakout board & PCIe cables.
There's a lot of different server PSU breakout boards on the market. They all perform the same function. Which is to allow you to use PCIe cables to power your GPUs off the server PSU. Basically, they act as an interface.
Some miners have taken things a step further and are modding their server PSUs by soldering them directly to the PSU as seen here:
Again you can probably guess I don't advise this mainly down to safety concerns. But also the fact that one bit of solder in the wrong place could easily fry your GPU array. You have to be very confident with a soldering iron and make sure you have the right pins soldered.
The 3 additional features that you'll find on a server PSU breakout board are as follows:
Voltmetre - this is a small LED display that will monitor the voltage output of the server PSU. Handy if you want to know yours have to correct voltage out but realistically a bit of a gimmick.
Power switch - this is a small switch on the breakout board itself which will allow you to turn on supply to the PCIe power connectors. I'm not a big fan of using breakout boards with this function mainly due to the risk of electrocution. Putting your fingers anywhere near the breakout board when there's power going to the PSU is in my eyes dangerous.
4pin Dual PSU power on the connector - this sounds like a great idea. Running a small cable between 2 PSU breakout boards so they power on at the same time. However, I can not find information on exactly how this 4 pin connector works or an actual cable and proper wiring diagram. There's also nowhere I can find the cable to make this work. Not to worry though as we cover how to power on all PSUs at the same time further down.
With those 3 features of breakout boards now a choice the only other thing we have to worry about is the PCIe power cables that will be going to the graphics cards and PCI risers.
The majority of high-end graphics cards for GPU mining require the following.
1 x 6 Pin PCIe (male) power cable (plugs into the top of GPU)
1 x 8 Pin PCIe (male) power cable (plugs into the top of GPU)
1 x 6 Pin PCI (male) power cable (plus into PCIe riser board)
So for each card you've got, you'll need at 3 PCIe power cables.
If possible try and get a breakout board that comes with PCIe power cables. They are usually a good length of at least 10 inches or more so you can reach the top of the GPU if it's in a frame.
I had a big problem with my breakout board and getting the right cables. There were no suppliers and finding a male to male PCIe cable on Amazon or eBay was like finding a needle in a haystack. I, however, did come up with a hack for this.
****Breakout board warning****
This was not obvious to me until I thought about it but all breakout boards I've seen plug directly into the PSU. The underside pins on these breakout boards are exposed. Whatever you do don't touch a breakout board when it's plugged into the PSU. Even if the power is off. PSU's carry residual power in their capacitors, enough to give you a bad shock.
Secondly, don't lay the server PSU and breakout board on a conducting surface. Use a wood frame or piece of wood. If you have a mental mining rig frame or sit the kit in your PC case you'll short the PSU and everything attached to it.
Finally, this might not seem obvious at the time but get a smoke alarm in place. Ideally something like the nest alarm which will ping your phone if smoke is detected. Your mining rig is going to be on constantly and with all those PCIe power cables and PSU's you do increase the risk of fire.
How to power on all PSUs at the same time.
If you're running two or more desktop PSU's you can use this cable:
However when running multiple server PSU's and/or a combination of desktop PSU's we don't have that luxury.
The best option is to go with an all power on switch. Run all the PSUs into the same gang/surge protector and power on at the wall or get a number of Y splitter IEC power cables.
Just remember that desktop PSUs usually have a power on button but server PSU's don't. Server PSUs will power on as soon as you send power down the IEC cable.
The other thing worth doing is setting your BIOS to automatically turn on when power is applied to it. This means that when you flick to power on at the wall everything powers up at the same time and you don't have to use a power switch/button for the motherboard.
This concludes our guide - I covered a lot of topics and you may have many more questions in your head that I can answer here. As such I've put together a shopping list for all the parts required to power your GPU's with a server PSU. If you have further questions or recommendation please leave a comment below.
Quantity obviously depends on the amount of graphics cards you plan on running. Re-read the capacity section if in doubt.
HP Platinum Server PSU
Breakout Board with cables
Nest Smoke Alarm
Low wattage PSU for mobo
IEC Y Splitters
Thanks for reading!
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Scott Millar // IT Rockstar