Low power/passive cooled CPU?

eeek · 3 Jun 2018 at 10:31

I think it then comes down to the following:-

Do you use openvpn? If you don't head for one of those pc engines' machines. Otherwise get a G4560 and a suitable fan cooler. The fan shouldn't ever come on (mine doesn't nor does Sgarrista's) and pick itx motherboard with 2 nic's and you are good to go.

It's a shame the thin itx motherboards seem to have totally disappeared. They only needed a laptop power supply so it removed another source of heat (the picopsu) from the case.

BongoHunter · 3 Jun 2018 at 10:32

Gimpymoo said:
Two

Have you considered ordering the Netgate SG-1000? It's from the company that maintain pfsense and is pretty good.

Or you could get an Asrock board and just add an Intel Pro dual port NIC, they have a lot of models so might be worth checking if any have dual Intel NIC already, https://www.asrock.com/mb/index.asp#Intel+CPU

Also worth noting to use all of pfsense features you need a CPU that supports AES NI

eeek · 3 Jun 2018 at 10:51

BongoHunter said:
Also worth noting to use all of pfsense features you need a CPU that supports AES NI

My box says AES-NI CPU Crypto: Yes (active) so the G4560 has it.

From my search online (most sites are nowadays awful at allowing you to search motherboards by feature) most of Asrock's ITX boards have dual nic.

LuckyBenski · 3 Jun 2018 at 11:05

Ice Tea said:
I'm guessing it's Bios controlled that it changes the clocking on the fly , i wouldn't want it permanently set at that.

TDP-down is basically a checkbox setting in BIOS. it's like having a choice of two TDPs, whether you call one Turbo or the other low power mode. But it's a set and forget thing really, unless you're a complete tweaker. Dead handy for ultrabook i7s though!

LuckyBenski · 3 Jun 2018 at 11:42

I have an i5-3470S with a large passive heatsink. I think that's a 35W TDP and it's a great machine, though it does have case airflow. That's also tuned to silence, with fans from 400-600RPM. If I remove the graphics card the entire machine is whisper quiet even up close.

So, a lot of it depends on your case and fan/not fans arrangement. Massive heatsinks are your friend.

Gimpymoo · 4 Jun 2018 at 09:57

eeek said:
Do you use openvpn? If you don't head for one of those pc engines' machines.

I am not using VPN right now but it is very likely I will do in the future which is part of the reason for this build and using a few other features, such as a proxy.

I am not against the idea of using something like that but I had my heart set on a 1U rackmount. Part of the reasoning is that I think it would look cool and secondly, I like something I can upgrade and/or replace components if faulty as needed. Those AIO units are great but just a little restrictive maybe?

eeek said:
It's a shame the thin itx motherboards seem to have totally disappeared.

As you say, they would have been PERFECT for this build.

BongoHunter said:
Have you considered ordering the Netgate SG-1000? It's from the company that maintain pfsense and is pretty good.

Or you could get an Asrock board and just add an Intel Pro dual port NIC, they have a lot of models so might be worth checking if any have dual Intel NIC already

I did consider it but for the price, I think I can build something with more "oomph" for proxy/VPN etc.

I do already have a few PCIe x4 cards I can use in a build.

LuckyBenski said:
So, a lot of it depends on your case and fan/not fans arrangement. Massive heatsinks are your friend.

Low power/passive is my aim, i say passive, am realistic, not nuts so the PSU will have a fan but the choice of 1U PSU's is limited anyway from what I can see.

Underclocking is an option if it helps to achieve lower power/low temps.

As it stands, the G4560 is the winner at the moment, still though, a 54w TDP is waaaay too high so all depends how low I could get that.

https://ark.intel.com/products/97143/Intel-Pentium-Processor-G4560-3M-Cache-3_50-GHz

The Pentium Gold G5400T would be a great choice with its 35w and even lower 25w configurable TDP but that is not released yet and will likely be priced at double that of the G4560.

Can underclocking cause stability issues?

Thank you for all your input.

DarkMatter · 4 Jun 2018 at 10:25

I've run several CPUs passive. Just keep downclocking until you hit a stable temperature. I ended up with:

3570k @ 3 ghz load temps of mid 60's - Thermalright MR02
6100 @ 3 ghz, load temps of mid 60s (small case + heatsink) - Arctic Alpine 11 Passive

Fully loaded with no case fans etc.

I will add that even adding the slowest fan onto the case + heatsink makes a massive difference to temperatures. Everything is a balance of power to heat, it really depends how much performance you need for the task you are doing.

Gimpymoo · 4 Jun 2018 at 10:37

A slow/quiet fan would not be an issue, am sure the PSU would be louder.

I have not got "silent fever"

Regarding the underclock, I think the CPU will be running at a quarter load, tops, so I would hope that leaves a lot of room for flexible cooling

DarkMatter · 4 Jun 2018 at 10:43

At the moment I'm running the 2400G underclocked to 35W with the HR02 with just the one system fan. Seems to get much warmer than my previous intel CPUs with temps in the 60s and low 70s on a hot day. I think I would have to downclock to 2.8-3 to get it fully passive, unfortunately I need the power as some software I use heavily taxes single cores.

As a side note a big benefit I've found is that completely passive PCs have significantly less dust!

Gimpymoo · 4 Jun 2018 at 10:58

eeek said:
It's a shame the thin itx motherboards seem to have totally disappeared

Been looking around and there are a few available but taking into account "which power adapter works best" issues and no SATA port etc etc, seems too much faff.

Gimpymoo · 4 Jun 2018 at 15:10

CPU is sorted, am going with the Intel Pentium Gold G5400T.

https://ark.intel.com/products/129949/Intel-Pentium-Gold-G5400T-Processor-4M-Cache-3_10-GHz

Runs 25w at 2.1Ghz.

I could downlock that even more I reckon to achieve a lower power draw and temps.

Will use a https://www.arctic.ac/uk_en/alpine-12-passive.html when I can find one in stock anywhere

6 year warranty though although I am unsure how often a lump of metal can fail under warranty?

Now, board and RAM..

H310 chipset?

Ice Tea · 4 Jun 2018 at 23:59

New Silverstone Nightjar NJ450-SXL fan-less PSU

SFX so smaller than a normal power supply.

Gimpymoo · 5 Jun 2018 at 15:01

Ice Tea said:
SFX so smaller than a normal power supply.

Would it fit in a 1U rack?

Gimpymoo · 5 Jun 2018 at 15:01

Also, getting hold of these low powered "T" variant Intel Sku's is a proper pain in the butt. Not giving up though

Ice Tea · 6 Jun 2018 at 01:00

SFX and 1U are completely different dimensions.

I wouldn't personally rush into buying brand new expensive parts for a pfSense box until there is a permanent fix for side channel attacks such as Spectre, meltdown , Throwhammer and Nethammer as all the current attempts to fix it slow the computer down and you're already at a disadvantage with low power and clock speed.

Unless you've already been using pfSense and love it i would experiment with an old computer with 2 network cards first before spending a large sum of money on it as i've lost count of the amount people i've seen build a pfSense or Freenas style box around the forums that endup going back to an off-the-shelf box Router or Nas as something simple and cable tidy that you just plugin.

Gimpymoo · 6 Jun 2018 at 10:16

Ice Tea said:
current attempts to fix it slow the computer down and you're already at a disadvantage with low power and clock speed.

From what I can tell, 4 threads at 2.1Ghz are not going to cause any problems punching through that. We are not talking an Atom or ARM chip here.

Ice Tea said:
Unless you've already been using pfSense and love it

Running it through a VM with an Intel quad NIC and do indeed love it

Never been a fan of domestic grade routers for a LONG time but likewise, £200 on so called "Premium" low spec routers is a joke.

PfSense ticks all my boxes and I get to play with computer stuff in the meantime. What is the fun in plugging a cable into a box. I like to know how stuff works.

Gimpymoo · 8 Jun 2018 at 14:11

OcUK to the rescue.

Been able to order the G5400T through them. Thank you @Ice Tea for the recommendation. It really is a powerhouse of a "low power" CPU.

The fact these are soo difficult to find, are people just not interested in low power parts or are they just a "niche"?

The Alpine 12 does not seem to be in stock anywhere yet.

I have some DDR4 2400 4GB RAM spare so that will do nicely.

Just need board, PSU, 6U server cabinet and a 1U or 2U case and good to go.

I got a WG Green 120GB SSD to install PfSense to and I know the whole build seems overkill but when you add Proxy, 1Gb internal LAN traffic and full firewall functionality into the mix, it is not too over the top as it first seems.

Freddie1980 · 8 Jun 2018 at 14:34

Does it need to be x86? Could you not run it on something like a RaspberryPi?

Ice Tea · 8 Jun 2018 at 14:47

Gimpymoo said:
Been able to order the G5400T through them. Thank you @Ice Tea for the recommendation. It really is a powerhouse of a "low power" CPU.

The fact these are soo difficult to find, are people just not interested in low power parts or are they just a "niche"?
.

The G5400 and G5400T was only just released at the start of April.

Gimpymoo said:
The Alpine 12 does not seem to be in stock anywhere yet.

It was only just released a couple of weeks back and you can't even order it yet from their website yet.

Plenty of places still have the original Alpine 11 passive that is just bare silver alluminium , not sure if the Black Anodising of 12 makes much difference but i've not seen any reviews yet.

Gimpymoo · 8 Jun 2018 at 14:49

Freddie1980 said:
Does it need to be x86? Could you not run it on something like a RaspberryPi?

I do not believe a Pi has the full instruction set required but I see no reason why it would, this is not what it was designed for.

I maybe wrong but that is my understanding.