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Is it ok to run fanless?

Posted: Sat Sep 15, 2012 8:37 am
by Madman
Recently I started a topic about 100% silent Linux server - viewtopic.php?f=29&t=83332

The hardware has arrived, and the PC is built. The only question remains about cooling.

Just to repeat, the system is built as follows:
Intel D2700DC (CPU + Mobo + GPU)
4GB Corsair value RAM
Seasonic X-400 Fanless PSU
Thermaltake V4 Black Edition case
+ DVD drive
+ Intel SSD

Now the question is - is it safe to leave the system with no fans at all, or should I leave the rear exhaust fan operational?

I'm currently running a stress test 'dd if=/dev/urandom of=/dev/null bs=1024 &' x4, with all cores pegged at 100%. And there is a little warmth above the top grille. The PSU seems to be completely cold, but the heat sink on the Atom is a bit warmer. I can touch the heat sink and it's warm, but if I don't remove the hand for 10+ seconds it starts to get hotter than I would prefer.

It's also autumn here, so the room temperature is a little lower than in summer.

Since the PC will be running 24/7 in a living room or bedroom, I would like to make sure the stupid fans can't be heard.

So far it seems that it should be fine, as I can touch the heat sink, and there is no way I could touch a modern GPU when under load, so I'm thinking running fan less should be ok.

The convection should take care of everything, right?

Re: Is it ok to run fanless?

Posted: Sat Sep 15, 2012 9:47 am
by Chrispy_
Madman wrote:
The convection should take care of everything, right?

Yep, especially in a case that large for a board that small. It's not too far off an open testbed in terms of thermal constraints.

A 10W CPU on a heatsink that large wouldn't need a fan. I would expect it to be hot to the touch but I've seen smaller heatsinks on 25W GPUs

The PSU is cold because it's barely operating.

Re: Is it ok to run fanless?

Posted: Sat Sep 15, 2012 10:18 am
by Bauxite
Way overkill psu for that, there is another passive atom board that uses its own DC input that would've fit the bill. Or pico psu etc...

Putting your hand on a heatsink turns you into part of the heatsink, so your hand getting uncomfortable over time is normal with something active.
Your hand/wrist area is actually one of the bigger heatsinks for the human body if you factor out evaporative cooling.

Re: Is it ok to run fanless?

Posted: Tue Sep 25, 2012 9:46 pm
by DPete27
Try downloading a program like HW Monitor. That will give you actual temps that can be reported to the TR gerbils, rather than "it feels hot to the touch"

Yeah, that 400W PSU is wayyyyy overkill for that system, but you already knew that from your previous forum thread. Many Atom systems do come with 90W DC power bricks like a laptop as Bauxite pointed out....Oh well.

Re: Is it ok to run fanless?

Posted: Tue Sep 25, 2012 11:38 pm
by MadManOriginal
Personally, I like to have some active cooling even it only serves to prevent localized pockets of hot air. You can do this and keep it 'silent' by running a larger fan (120mm+) at very low speeds, and other tricks like making sure it doesn't have a direct line of sight so to speak to the exterior.

But, is it 'ok' to do this? Yes, as long as there is a decent path for convection airflow. Ideally the bottom and top of the case, not the front and back, would be vented but a regular case should be ok too.