This is probably a stupid question, since 2 > 1, but here goes…
I have a home server. It’s a ComputerLINK 1U rack server I bought off eBay some years back. It has 2 CPUs, Intel Xeon E5645 2.4Ghz(https://ark.intel.com/content/www/us/en/ark/products/48768/intel-xeon-processor-e5645-12m-cache-2-40-ghz-5-86-gt-s-intel-qpi.html). It also has two 750W power supplies, but I have one unplugged. It also has RAM and 5 HDDs.
I also have the guts of my old desktop PC. The CPU is an AMD FX8350 4Ghz(https://www.amd.com/en/products/cpu/fx-8350). The motherboard is some ASUS model, I forget and don’t want to check right now. A potential PSU would be 500-600W range.
My question: I am considering moving to use my old PC parts as a new home server. One benefit is to cut down on the noise (rack mount PC fans are LOUD). But the real gain I would want is on power savings. So, if RAM and the multiple HDDs all stay the same, but I moved them to the AMD/ASUS CPU/motherboard, can anyone definitively say this will be more power-efficient?
I am not very knowledgeable when it comes to electrics or power consumption, and am just looking for someone to confirm for me. I am aware that the AMD CPU still isn’t an excellent choice for an always-on machine, but it could be an improvement.
A few points:
- The redundant (second) PSU on the server is not using power (at least, not much) unless the other fails. Its job is to be available if the other PSU fails, or if power is lost (you typically have them on different PDUs and fed by different UPSs.
- Almost any desktop is going to use less power than a server, as servers don’t bother with power-saving features or power states other than full tilt into oblivion.
I won’t go into the research required to give you a quantitative analysis, but suffice to say that a server > desktop in terms of power usage IN MOST CASES. Of course, if the desktop is running four 250w GPUs and running crypto or other full-time workloads, it could exceed the server, but all things being equal, well, you get the point.
While actual power consumption won’t be much apparent power (VA) will be a measurable amount. If you’re connected to a UPS and it’s not a super modern server then it’s apparent power will be a decent amount. As a normal end user you don’t pay for this, but if you’re trying to spec out a UPS you’d want to calculate it and factor it in.
The FX 8350 isn’t a very power efficient CPU, but two E5645 in a server is going to use a lot more power at idle (and load) than the FX. Servers actually have pretty manageable power usage, but idle consumption of a dual CPU system will always be more than a single CPU system.
Well-said.
This is pretty much all I needed to hear. Thank you :)
Why not plug each into a Kill-A-Watt and measure it at idle and under load?
This seems like the right approach.
You are right that this is the true way to tell, but I don’t own one, and the “new” PC is not set up at all. I would have to tear apart the old and build the new to be able to test the new one.
Why not check online for each component for its max watt?
AMD FX8350 is 125W max Xeon E5645 is 80W max
Then the only difference is the motherboard, right?
And also, the Xeon has integrated graphics but the amd does not. If you will let the amd do a lot of things with video, it needs a video card or else the cpu will need to do all of that. On the other hand, if the machine main task is to for example render videos, an integrated GPU in the Cpu will not get you far either…
It depends on the application/duty, but maximum/rated power is not usually relevant for power consumption on home servers like this - they’re rarely running at mother than a few percent load.
Idle power consumption is the main concern. Server boards often have a lot of NICs and chipsets that don’t idle well. Consumer gear is generally much better for that.
Neither Westmere nor the AM3 platform are known for low power consumption. A modern LGA1150 or later desktop platform would probably be preferable.
You are absolutely right. Assuming the home server is probably not serving thousands requests every minute or mining bitcoin but just a file server or something that is idle most of the time.
Max wattage would be under load. OP has said the PSUs are rated for 750 vs 600 (potentially 750x2 if they plug the rack’s second psu in).
That’s your max usage right there. But that’s assuming everything tops out and it’s not a valid assumption.
In any case I suspect the pc will be more effecient on account of the server basically being overkill. Substantial overkill.
I do not agree with that.
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A PSU is the maximum what all the components combined are allowed to use. No more power than that is possible. If a system needs more than it’s PSU can deliver, it will become unstable (data loss, random restarts, etc.)
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The 2x750 is a redundant setup that servers have. Servers need to be able to run 24/7. With redundant PSU if one PSU has a failure, the other PSU will take over. Without any restarts. You can just pull the plug out of one of the PSU and all is just fine.
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I do agree with you that the max wattage is under load. Most home servers are running idle most of the time anyway.
that’s why there’s 2x 750’s instead of a single 1500 watt, yes. but they’re frequently capable of drawing more than the 750 watts under high demand loads. which is kinda why I put that bit in parenthesis. The OP has said they have it unplugged.
first point is literally what I said.
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I don’t know how much that 8350 uses at idle, but that cpu is really old now and certainly not known for being power efficiënt. Honestly I think you’re better off getting something more modern, if you buy used it doesn’t have to be expensive either.
Question: does your home server Need to be powerful for what it does? Would a mini desktop PC or a single board computer be able to do the same job as your current setup? Of your main concern is truly power savings, consider those options. Most mini pcs maybe draw 60 watts, most laptops only draw around 15-20 watts, most SBCs only draw around 5 watts max.
The best way to increase energy savings on your currently owned server would be to upgrade your PSU and not motherboard. Get a gold rated PSU certified by energy star as it has at least 85% efficiency. Invest in a kill-a-watt measurement device that plugs into the outlet so you an see exactly how much wattage you are pulling and how much you manage to cut down.
