It’s a good idea until you consider the fact that a Raspberry Pi will be astronomically more power efficient.
If you think in flops per watt, maybe a little bit, but not a lot. Do you have one or two good procs for almost free, or half a dozen new sbcs at $100 each? Takes a while to save back that amount in power.
My question is usually not how many flops, but how quickly and reliably those watts can give me just a few flops on demand.
A RPi is going to be smaller, quieter, and 10x more energy efficient though…
There are probably a dozen things you can do to save energy on orders of magnitude higher than using a pi.
Then do them. It’s still not going to decrease the energy use of your server.
Like: using the pi to manage your HVAC more efficiently.
Why use a pi instead of a microcontroller?
At the HVAC control level it would be a Pico - for the development / maintenance time efficiency: I know how the tools work, I know the community support is there, the hardware is easy to find and available relatively reliably, although ESPHome on the ESP micro-controllers is pretty good too.
Also, Raspberry Pi first got popular because of the size and cost. Now it’s popular because it’s popular. Not hating on them, I think they’re cool, but they’re not cheap any more. Especially with the scalping.
Getting x86_64 based systems is going to mean much less headache. Unless you truly truly need the size I wouldn’t consider getting a Pi or other SBC. Just go to literally any used marketplace (Facebook, Craigslist, etc) and get anything.
but they’re not cheap any more
People say this, but they really are still cheap.
The original Raspberry Pi Model B launched for £22 in 2012. The entry level Raspberry Pi 5 is £46, but adjusted for inflation that’s only £32 in 2012 money. So only £10 more expensive in real terms.
Raspberry Pi Zero 2 W is only £14.40, which is only £10 in 2012 money. Compare this to the original Raspberry Pi Model A, which launched for £16.
People look at the headline cost of the high end RPi 5s (£115 for the 16GB model, £76 for the 8GB), but fail to recognise that there was nothing comparable to these in the Raspberry Pi lineup before, and these are not the only models in the Raspberry Pi lineup now.
There was the supply shortage price spike, they really were stupid expensive then if you supported the hoarder/scalpers.
Since that has cleared… most of the Pi price increases (in inflation adjusted dollars) can be attributed to improved features like more RAM, or people acknowledging that having a good dedicated $20 power supply is preferable to dealing with the flakiness of that old phone charger you found under the bed.
10£ more, or 50% more expensive?
Don’t like the expensive version? Get a Zero 2 W which outspecs the original by a wide margin.
Sure, but the specs aren’t directly comparable.
They also still manufacture the RPi 4, which starts at £33- which is £23 in 2012 money.
Inflation adjustment doesn’t really tell the whole story though, it’s not like salaries have gone up by the same amount. Regardless, I don’t like dealing with the Zero unless I specifically need something that tiny. It’s just too annoying. Don’t get me wrong! They’re cool! I’m just saying unless I really need a Pi Zero I wouldn’t wanna work with one. I’d rather work with x86_64 than Arm. Like even just getting Java working was really tricky on Zero. Much like a microcontroller has limitations for what you can run on them but they have other benefits, Zeros aren’t really general purpose.
So yeah, dirt cheap used laptop for general purpose server beats out dirt cheap Pi in my book.
That’s only true for the high-end Pi 5. Lower-powered models like the zero 2 are still cheap, and they’re a lot easier to find than a few years ago.
Which part? Because the “it’s not x86” is even more annoying to deal with on Pi Zero lol.
Pi is popular with me because it’s time efficient. Meaning: when I am trying to get it to do something, it takes less of my time to make the thing actually happen on Pi hardware as compared with most of the other small / embedded alternatives. Notable recent exception: ESPHome on ESP32 hardware, but even there the more limited variation of Raspberry hardware makes it similar to those fruity phones, MP3 players and computers - since there are a limited number of variations, you can usually find information specific to EXACTLY your setup, instead of having to infer from something almost the same, but figure out little wrinkles here and there due to differences between what you are working with and what you are reading about on the internet.
All computers are single board computers if you take out their guts and tape them to a board
And they passively cool better that way much of the time too…
Technically a Pi is a single chip computer but they’re called an SBC because they replaced stuff like a Motorola 68HC11.
Yeah… no. Old laptops idle at around 50 °C.
That just means they become 100% efficient in winter!
Idk, heat pumps have become a lot more popular in recent years.
my 20 year old pc runs at ~5°C above room temp under load
You really shouldn’t be spending your days in a room at 45 °C.
you are joking, but my room actually feels like that.
So do Raspberry Pi?
Get a slightly bigger heatsink.
You’ll have no end of problems and won’t know whether it’s a hardware or software problem.
Damn straight. Another reason not to buy a pi.
Only if you’re running it at full load all the time and comparing that to a comparable number of raspberry pis it would take to do the same amount of work. Also, only if you live in a cold climate and the heat generated is not a concern and power is supplied by a renewable source so power isn’t a concern.
Yeah… I’m not going to stick a clunky old laptop on top of my bookshelf and have it run 24/7 as my PiHole. My Pi Zero 2 W is far more appropriate.
No reason why a laptop wouldn’t work though.
I mean, a lot of things would work, I could power it all with potato batteries if I had enough. The Pi Zero 2 W only cost ~£15 anyway.
I agree that the Zero is up to the task, but I prefer a wired connection for my home DNS/DHCP server and if I understand correctly the Pi5 has better wired ethernet than its predecessors… Yeah, utilization is laughable, but there’s something to be said for reduced lag time too:
Hostname: pihole CPU: 0.2% on 4 cores running 318 processes (0.3% used by FTL) RAM: 25.9% of 2.0 GB is used (7.4% used by FTL) Swap: 35.9% of 512.0 MB is used Kernel: Linux pihole 6.12.25+rpt-rpi-2712 #1 SMP PREEMPT Debian 1:6.12.25-1+rpt1 (2025-04-30) aarch64 Uptime: a month (running since Sunday, May 18th 2025, 17:54:59I have never felt the need to have a wired connection for my DNS/DHCP, since such a trivial amount of data exchanges hands. The quality of the wired connection if it had one would similarly have negligible impact, surely.
For me it’s not about the bandwidth, it’s about the lag and reliability. I have had strong WiFi connections flake out a lot more than wired connections.
Also, I just prefer to not have 100+ WiFi devices kicking around my network when more than half of them could be wired, or on another protocol like Zigbee.
I guess I am pretty far from saturating my WiFi in any way, the removal of cables with little to no impact on connectivity was far more of a priority for me. I have never noticed a WiFi related outage or performance loss.
I will say this: we had a big lightning strike a few years back and it conducted into the house via the internet cable, then spread via the ethernet cables taking out everything that was wired (over $7K in damage) - devices connected only by power and WiFi were mostly spared.
My WiFi routers have historically struggled a bit, I’ve got a decent one now, but even it is slow to manage the DHCP lists for fixed assignments by MAC address.
But… that’s so uncool…
I should have rebuilt an old coffee maker in to a Pi Hole instead. I’m such a rube.
Its all fun and games until the power bill arrives. Performance per watt is important, please look at that first. Don’t be me.
Alternative. Cheap android box and coreelec.
You can have them for about 20 bucks. Have minimal power consumption. And small power factor. They also have ARM architecture.
They are good for low power applications.
I’m sure silicon valley are stepping on each other, vying to get their hands on these super cheap laptops for their 24/7 AI training.
No Silicon Valley are the ones throwing these things away because it costs them too much money to deal with old unreliable PCs.
Damn, I should have ended the post with /s for people like you.
They aren’t very useful for much besides hobby projects. Modern hardware is more energy efficient and will be cheaper in the long run compared to anything that would be considered e-waste. The only advantage an old laptop has is the initial cost, so it makes sense for a small home server.
Look for refurbished elitedesk g5, it runs debian magnificantly! I splurged a bit on the memory and ssd and have a quite nice desktop (developer).
this is the way
damn you all, now I impulse bought an old thin client for 30EUR :-) but, fwiw: I mostly use RPi for my purposes, up to RPi4; RPi 5 I think missed the mark, with its active cooling requirement and power use. (and price…) the only use case where an i86 alternative is justified is my jellyfin setup (where realtime transcoding is needed).
As a Pi Hole, the Pi 5 doesn’t require active cooling.
Now, I am running a separate Pi 5 with a HAILO 8 for Frigate monitoring of a bunch of video streams, and it does need a little air movement, so I built a box with a 200mm fan pulling through a filter and I just threw all my Pis in there along with the Frigate rig so they stay nice and cool… I’m thinking that I should probably switch Frigate over to a Pi 4 for the h.264 hardware decoder, but the 5 is working fine for my needs and endless tweaking gets boring…
You are probably right for something like a Pihole, which can easily run on a RPi 3 as well (I think I’m running it on a 3… maybe even a 2.) My fear is something like Jellyfin (which it is not suited for anyway, I know), combined with the fact that my stack of Pis is in my meter cabinet, so a fairly confined space with very little air movement, also passive. Running Jellyfin without transcoding has my Pi 5 running at just under 50 °C.
It’s impressive what a gentle breeze will do - if you can get a fan on your cabinet it will help a lot.
I filter my air and positive pressure the cabinet so the dust doesn’t build up (as fast).
I had the accounting self hosted web app on it until I was too lazy for accounting and now I am in so called hot water and must make bunch of shit up using mathematical apparatus
But it worked really well for a year or so
It’s not just the size constraint. The power usage is significant…
Fake news. Modern RPis need up to 25W PSU. Even old laptops could idle lower than that, as otherwise they wouldn’t be able to get significant battery life. Turning off the screen will also really lower their power consumption.
You’re comparing a laptop at idle to the power supply for a pi that needs to power it at full load plus overhead and inefficiencies. That’s like comparing apples to an orange tree.
I mean sure. If you want to compare actual efficiency then performance per watt is the metric. Here a laptop would easily win as it has higher performance for similar power. The TDP of a U class processor is only 15W normally. It would obviously help to disable things like Turbo Boost as well. Said laptop having more performance wouldn’t need to stay at high power states for as long as the Pi either as it takes less time to process requests. Returning back to idle faster is a big advantage.
If you have the lid closed, you’re looking at 3 to 15 watts to have a laptop running in the background doing some basic server shit.
Maybe a little more under high load, but those are going to be intermittent and not constant.
I’m just saying it’s not that much more electricity usage, and the recycling more than offsets the CO2.
Not quite. Unless the system has pretty advanced power management and is using very recent technology with high density, it’s unlikely that an x64 chipset will use less power than a comparably powered arm64 chipset. Not just the processor, but the smaller board is actually a power saver and allows it to generate less heat meaning both less power wasted and dissipated as heat as well as less power needed for fans to properly dissipate the heat. I’ve never seen a laptop use 3W at idle when considering the whole device, maybe just the CPU, but not if you include the rest of the components like RAM and disks and power supply. And especially true in a laptop that is old enough that it’s being recycled. Heck, the power supply and charger alone might be using 3W at idle with full battery.
With a raspberry pi 4, the typical power usage for the 2GB RAM model is 5W under load for the whole device and about half that for idle. Add a couple of watts for the extra memory and wider bus on the 8GB model and other things can add to that, but that’s mostly accurate. The pi 5 is a little more and the 3 is a little less. Of course, the efficiency of the laptop at full load might end up being better than a comparable number of raspberry pis it would take to do the same amount if work, but comparing a single pi or any other reputable arm-based, single board computer to a single laptop at idle is always going to be that way.
Battery charging circuits don’t operate continuously when the device is charged. Pi also still needs a PSU, typically a phone charger, and for a server application would need an SSD or HDD in most cases. SD cards have lower performance, write endurance, and capacity after all. A single raspberry pi couldn’t match even a somewhat old laptop in performance. In terms of actual efficiency (performance per watt) Pis don’t do that well as they are using cheap processors made using old core designs and even older process nodes. Even the latest Pi 5 uses a 16nm process node with a core design from 2018. A 10 year old laptop might have 14nm process node which would be better. This means that a laptop would have more performance, so even if it had more power consumption at peak it could still end up with significantly better performance per watt, and that extra performance allows it to idle more often as it spends less time processing requests.
Of course the ultimate in performance per watt is always going to be a modern high power server or an Apple Silicon device. Mini PCs can also do well for home use, and are much lower power so better suited to less demanding usage, and have the best performance per watt for consumer devices. The M4 Mac Mini for example is pretty much best in class in performance per watt, and low power consumption at the same time.
Battery circuits come on enough to be a load that needs to be considered and will show up if you measure load on the device vs load consumed by the components connected to the power supply. In terms of low power devices, it is significant, though not the primary concern. But compared to the pi PSU, the charger not to mention the battery and internal PSU of a laptop, consume way more power and produce way more heat.
All of the rest assumes needing always on, heavy load processing which isn’t what the post I replied to was talking about. I was specifically replying to idle power load. And in my case, even with a bunch of self hosted applications, most of the time my servers are idling. If I was running a virtualization farm or something that was always under heavy load, then yes, as I mentioned, a single board server isn’t ideal.
As for disks, I don’t use SSDs on my pis except one that actually does a lot of local data processing. Everything else runs in memory and stores persistent data on my NAS, including logging. Virtual memory/swap is disabled on all and things that need temporary storage/cache of small amounts of data is cached on RAM disks where applications can’t be configured to not use disk caching. The only need for the SD card is for boot and some minimal IO needed for local OS operation. I have a Raspberry Pi 3 B i got about 8 or 9 years or so ago with the same SD card in it.
They aren’t what I use as a database server, obviously, but they are extremely low power compared to what an old laptop would need and work great for things like pihole, and other network applications as well as being a part if my home kubernetes cluster and run the majority of the cluster’s processes on demand.
If you have the lid closed, you’re looking at 3 to 15 watts to have a laptop running in the background doing some basic server shit.
Not all laptops make effective use of power with the lid closed, sadly. Not saying this as a correction, but for others to know that they need to make sure these settings are available in the bios of the system they are buying.
Laptop performance when closed is quite variable, but depending on where you live, each 10W of idle consumption 24/7/365 could cost you somewhere around $20/yr (assumes @$0.20/kWh, YMMV). This isn’t overwhelming on it’s own, but it is “cost difference between a junked laptop and a Raspberry Pi” kinda money.
And you are often paying 140-200 for a pi nowadays to make it have the same usability as a laptop (pi, power supply, sata hat, data drive because SD cards simply fail after a while under server IO) while you can get cheap used laptops for 0-100.
So unless you are running it for more than half a decade (which rarely happens with selfhosters for a main server), you are probably spending more in total on the pi.
I think SD card failure rates are way overblown if you’re buying from reputable manufacturers (Sandisk, Samsung). I’m sure they do occasionally fail, but I’ve never experienced one.
You’re right, for really intensive tasks the costs can climb, but I see people asking for ideas for what to do with a junk laptop and the top suggestion is always something like pi-hole or a bookmark manager that could run on a potato.
Like with most things in life, it depends.
I have a high fail rate with Samsung SD cards. Oddly the cheap-o no name ones haven’t failed yet.
I used to think so too, but my pi-hole just died the other week after four years of uptime. Couldn’t work it out, finally pulled the SD card out to reinstall the OS and found my laptop wouldn’t recognise it.
Made me glad I don’t run my mailserver on a Pi anymore!
I join you, I used to change SD card and USB disk every 1-2 year. I bought a nas 3 year ago didn’t need to change disk yet.
Laptops are not generally designed to run like that with a closed lid. Heat dissipation is designed around the idea the laptop is open and some of it is through the keyboard surface. The lid closed would change that.
Systems can of course be setup to power off the display but for server/service uses open laptops may not be efficient space wise.
Having said that if the scenario is low power use the heat dissipation may not be a major issue. But if there is an unremovable battery i’d still be concerned about heat dissipation with the lid closed and even just the battery itself regardless of heat dissipiation.
Just remove the lid entirely.
really depends on the laptop. a lot of laptops exhaust off the side.
Not so sure about the last part. It takes ehhh about 3kg of c02 to produce 1 Watt for a year. Carbon footprint to build a laptop is about 200kg or so, but you’re not offsetting one of those you’re offsetting the raspberry PI you WOULD have bought which is just a small fraction of that. After a year or 2 you’ve almost certainly burned through your c02 savings if it’s on all the time.
A raspberry pi is not as efficient as people are claiming. They need up to 25W PSU for a reason. Laptops can idle lower than that certainly. Something like a MacBook Air M1 would idle in single digit territory, as would any netbook basically ever made. Only really high performance or older laptops have idle power draw issues since battery life is a major selling point of a laptop. Said laptop is probably also faster than a raspberry pi. The people building Pi clusters are really not doing themselves any favors with power efficiency.
Nah no way does the average ewaste tier laptop use less power than a raspberry pi for any given task. The power consumption floor for a laptop may be lower than the rpi ceiling but that’s not a fair comparison
Benchmark it and tell me. The truth is that most RPis are made using older process nodes to reduce costs. Laptops are often made using the best avaliable process node and core design. A modern raspberry pi 5 uses a 16nm processor with Cortex-A76 design from 2018. A laptop in 2015 would be using 14nm Broadwell processors from Intel. This was a time when 15W U series processors were gaining popularity, so sustained load power consumption is quite low. A 2015 laptop is 10 years old, and wouldn’t run Windows 11, so will be ewaste this year. Same with a lot of 8 year old machines actually.
