Hardware sizing: Is a 345W Server PSU total overkill for a dedicated OPNsense bo

[dahapo8728]

Hi everyone,
I've been lurking here for a while, picking up tips on how to transition my OPNsense setup from a virtualized environment in Proxmox to a dedicated bare-metal machine. I finally pulled the trigger on a refurbished 1U short-depth server that I found for a steal. My main goal is to get the "heart" of my network off my main compute node so that the family doesn't lose the internet every time I decide to reboot my host or experiment with a new container.
The specific point I keep running into when reading through hardware recommendations here is the heavy focus on ultra-low power consumption. Most people seem to be running N100s or older Atom boards that pull maybe 10-15 watts. However, the server I picked up came equipped with a Server Power Supply (345-Watt). It's an enterprise-grade unit, and honestly, it looks built like a tank, which gives me some peace of mind regarding 24/7 reliability.

A small personal insight: I've had consumer-grade wall warts and cheap desktop PSUs fail on me in the middle of the night more times than I care to admit. There's something comforting about the "industrial" feel of server hardware; it's designed to be hammered for years without a break. But I'm a bit worried about the efficiency curve. If my OPNsense build—running an older Xeon E3 and a couple of Intel NICs—only idles at 35-45 watts, am I just throwing money away on electricity by using a 345W PSU? I know some of these server units are actually quite efficient at low loads (especially if they are 80 Plus Platinum), but I've never used this specific wattage range for a dedicated router before.

I'm also slightly concerned about the noise. Most of these server units have those tiny, high-pitched fans that sound like a hair dryer when they ramp up. In a server room, that doesn't matter, but my rack is in a ventilated closet near the living room.
Has anyone else here repurposed older 1U enterprise gear for their OPNsense build, and did you stick with the original power supply or did you find a way to swap it for something more "home-friendly"? I'm trying to figure out if the stability of server-grade power is worth the potential hit to efficiency and the acoustic trade-off.
Does the "reliability" of a dedicated server PSU actually outweigh the benefits of a modern, silent, low-wattage DC adapter in the long run for a home setup?

[meyergru]

An old rule of thumb says that electronics fail within the first 4 weeks or after 2-3 years, see https://blog.izm.fraunhofer.de/service-life-of-electronic-products/.

I have at least 5 of those Nxxx boxes running since 2023 and none of them failed so far. Also, most of them are passively cooled, which in turn saves the risk of a fan going out. When you look at the power draw, less power equals less heat and that in turn means stress and eletromitigation in the active components. If need be, I always have one laying around to switch out in case any of these fail.

I think that 1U servers are built for small space requirements, which causes a need for hefty fans in order to cool them down when compared to bigger PC cases when space is less of a concern. Also, servers are often used in business applications, where depreciation dictates that they will be swapped out after 4 years at most for newer, more powerful or less power-hungry generations - thus, in reality, long-term reliability is not so much of a concern. This also may give you a hint why those things are often sold used for a "steal".

On the other hand, small router appliances like AVM's Fritzboxes often run for decades without any problems.

So, in the light of power cost, I would always choose one of those Nxxx boxes for that job.

[Seimus]

Is a 345W Server PSU total overkill for a dedicated OPNsense

This is a wrong question. Because OPNsense itself doesn't have anything to do with the Power draw. Your HW does.
So basically your PSU should be equivalent and able to deliver the Power the HW needs in case of MAX load.

And of course such servers and possibly PSU will create additional heat and noise, mainly the 1U servers. Many users replace the servers fans with Noctua fans which comparing to stock are quiet. But overall you should be prepared for the server noise and extra heat generated.

Similar as @meyergru mentioned. I run as well NXXX nodes, Past the few years I had 3 N5105, N100, and now N355. All of them were used for OPNsense at a point of a time and than repurposed for Proxmox.

These devices have no problem to route traffic at their Line rate.

The point is what do you target with that server. What performance you want to achieve. Because these small form factor miniPCs are efficient enough to provide the performance usually a user can seek and are reliable enough at least per my experience.

Regards,
S.

[pfry]

[...]Has anyone else here repurposed older 1U enterprise gear for their OPNsense build, and did you stick with the original power supply or did you find a way to swap it for something more "home-friendly"?[...]

Several, but not for OPNsense. It can help... or not. It's a bit of a hobby with me, so I get pretty silly with it (link, link). The simplest is to replace the fans alone, and as I'm sure you are thinking, you just have to find quieter ones that perform adequately. Not always easy - there's native performance, but also PWM curves to consider. With a PC that should hopefully be adjustable in the BIOS. As meyergru said, the 1U form factor is not ideal.

My fan-cooled equipment tends to be bloody noisy, as I like to filter the air. It's a price I'm (usually) willing to pay.

[...]am I just throwing money away on electricity by using a 345W PSU?[...]

Perhaps. My own firewall has a max power consumption of ~200W and ~40W idle (120V AC) with a 650W PS. It's the smallest I could conveniently obtain. Is power cost such a concern that obtaining new hardware would be worthwhile? (Or would you have other reasons for such in addition to power?)

[RobertoZ]

[...]Has anyone else here repurposed older 1U enterprise gear for their OPNsense build, and did you stick with the original power supply or did you find a way to swap it for something more "home-friendly"?[...]

Several, but not for OPNsense. It can help... or not. It's a bit of a hobby with me, so I get pretty silly with it (link, link). The simplest is to replace the fans alone, and as I'm sure you are thinking, you just have to find quieter ones that perform adequately. Not always easy - there's native performance, but also PWM curves to consider. With a PC that should hopefully be adjustable in the BIOS. As meyergru said, the 1U form factor is not ideal.

My fan-cooled equipment tends to be bloody noisy, as I like to filter the air. It's a price I'm (usually) willing to pay.

[...]am I just throwing money away on electricity by using a 345W PSU?[...]

Perhaps. My own firewall has a max power consumption of ~200W and ~40W idle (120V AC) with a 650W PS. It's the smallest I could conveniently obtain. Is power cost such a concern that obtaining new hardware would be worthwhile? (Or would you have other reasons for such in addition to power?)

I think that's the first hot rodded router I've seen with a K&N filter on it. :)

[pfry]

I think that's the first hot rodded router I've seen with a K&N filter on it. :)

Heh. That was likely AC Delco. I use AEM or Airaid washable dry filters now... technically K&N, as K&N has eaten most of its competition (and killed their product lines). But traditional K&N filters are oiled cotton, not something I'd want on my shiny clean computer.

[connervt]

5HP gain, easy.

[nero355]

5HP gain, easy.

And +1 on top of that if you apply the sticker too! :P

I know some of these server units are actually quite efficient at low loads (especially if they are 80 Plus Platinum), but I've never used this specific wattage range for a dedicated router before.

Efficiency and the whole Gold/Platinum ratings story is something that needs a lot of reading about and browsing through a lot of Reviews too, so I would not "put it away" as easy as that! ;)


But I would like to mention one thing that I noticed after having seen a lot of Server types and models with my own eyes and heard them all with my own ears :

I think you will be happy with pretty much anything starting with something similar to the HPE G8 Servers that had Xeon E5-2650v1/v2 CPU models and also the Xeon E3 1230/1240v1/v2/v3 CPU models.
As long as these are set to anything else than the Performance mode their noise output is not that bad at all !!
I am not saying they are totally quiet, but for a Server they are pretty damn quiet at LOW LOAD which I am guessing at this point will apply to your OPNsense Router most of the time...

The later HPE G9 models did even a bit better I think so the newer the Server is than that era of hardware the better chances you will have to own a quiet(ish) Server working as your Router 24/7 :)

Also keep in mind that the whole world at some point very close to this era of hardware started demanding high efficiency and low power consuming hardware in Datacenters around the world because of all the "Eco Friendly" nonsense that you have probably heard one time too many about by now, so Server Hardware got less and less "that big old noisy box that consumes a shitload of power all the time" and a lot has changed in the meantime!

[BrandyWine]

Does the "reliability" of a dedicated server PSU actually outweigh the benefits of a modern, silent, low-wattage DC adapter in the long run for a home setup?

Is it a ATX PSU or just a simple single supply?

You have more factors in there.
1st, the server PSU you describe, is used.
2nd, the small dc-dc warts are mostly junk made. If you get a decent brand name (MeanWell or other), just buy two, keep one as spare.

There's also other external options, like just use a MeanWell RS-75-xx, you can simply house it with venting, silent and durable.

But you have a server unit, that has a PSU, so what would be the goto if you dont use the PSU that came with it?

[drosophila]

Wasn't Dell the vendor who just loves to swap pins on the PSU plugs to further customer-lock-in? If so, you'd have to reconfigure the replacement PSU pinout for the board. Also, these server boards tend to have sophisticated fault-detection that requires communication between components so it may refuse to run with a random PSU because it can't communicate with it.

Whether or not the PSU might be overkill depends on your hardware. If it can draw something around 300W then it's not overkill, even if it needs it only for some seconds, it needs to be there. Idle consumption is one thing, "normal load" consumption is what you're looking for (in a common household, that will however be close to idle).
The site you linked to doesn't say anything about certifications, the product details of a randomly picked one just says "Energy Efficiency: This power supply is designed to be energy-efficient, reducing electricity consumption while maintaining consistent performance.". The only way to know is to measure before and behind the PSU, under the most likely load conditions, or only measure line draw and compare with a known PSU.

In the olden days a PSU could be only 40% efficient if operating way below its rated spec. But keep in mind that these 60% waste are only a percentage of the power actually delivered, not the maximum. So if you draw 10W, it'll draw 16W from the mains, not 240W. I assume that this PSU is more recent and thus won't be this bad. Maybe 70%, so for your 45W you're looking at 13.5W wasted.
The oversizedness in itself is not an issue with PSUs. In fact, it means that it will run cooler and therefore last longer (possibly eternally). Server fans probably always run full tilt but if not this would be more silent as well than a 125W unit which might be only 5% more efficient.

[BrandyWine]

Wasn't Dell the vendor who just loves to swap pins on the PSU plugs to further customer-lock-in?

Michael Dell had Steve Jobs vision before Jobs did. ;)

I know 100% not every PSU for ATX/AT/etc are wired the same way. My xeon Asrock mobo was having an issue using one brand of psu (corsair), I then had to dig some, found out the PSU was not wired right for the mobo, so, had to buy another brand PSU (EVGA).

[nero355]

My xeon Asrock mobo was having an issue using one brand of psu (corsair), I then had to dig some, found out the PSU was not wired right for the mobo, so, had to buy another brand PSU (EVGA).

Wasn't that a Corsair issue at the time ?!

I can remember reading about something like that, but I don't remember the whole story anymore...


One thing I do know for sure :

If you are going to use DELL hardware in other/regular systems then you need to put some tape on a couple of PCIe pins.
A well known example is when using their LSI HBA Controllers !!



_{And I also have a Toshiba laptop where I needed to do this to the Intel WLAN NIC but that's totally offtopic here...}

[pfry]

Wasn't that a Corsair issue at the time ?![...]

A bit of an aside, but I'd be careful when buying from Corsair. They have a habit of introducing good products, and after the review cycle, quietly cheapening them (with the same name and same or very similar part number). I've seen this firsthand with both power supplies (105C -> 85C caps) and SSDs (reduced endurance flash).

[BrandyWine]

I was buying sets of Corsair products for pc builds (psu, fans, and liquid coolers). But after psu experience and problems with their support, I stopped using them years ago.

As for the 345w psu, the load power draw will be whatever it is. There's not a lot of loss if the PSU is terribly oversized. Thus the question about "overkill" is perhaps just a context question. If the load is 50w and you have a PSU capable of 345w, yes perhaps overkill but there's no ill side effect.