Brandnew system: Crash on startup when turning off casefan

Hi all,

I've just built a htpc for use as a media center/fileserver. Now I'm getting the strangest problem I've ever encountered.

First of all the system works fine if all fans are running at high speeds. But since this is a htpc I'd like it to be quiet. So I turned down the cpu fan from 2300 to 1600. But I have a small casefan producing noise, which I can't control through the bios, so I temporarily turned it off. After all, unless you're going to do some heavy processing and the case temperature get's hot, it's not really needed right? Wrong. If I turn off the casefan the PC crashes about the time you get that funny windows startup noise. The system simply resets. No bsod, no freezing.

So my first idea was, since the lack of a fan seems to be causing it, something must be overheating. I checked the temperature, both cpu and mobo are below the 30 degrees celcius. I turned on the case fan. Did some stress tests checked the temperature again. I haven't seen 30 celcius yet. I have turned off overheating protection in the bios. Still the same result.

Right now, I'm stumped. I want my htpc quiet, but apparently it needs noise in order to live. What the heck is going on?

My system:
Motherboard: Asrock H61M
CPU: Pentium G620
Memory: 8 gb corsair something or other. 2 sticks. (Tested them)
PSU: Nexus 5000 (Overkill I know, but it's quiet)
harddisk: Corsair P128 SSD

8 answers Last reply
More about brandnew system crash startup turning casefan
  1. You mention the CPU and motherboard temp at 30c. What is motherboard temp? I don't believe I have ever heard the term. Could this be case temp?

    Are you are using some program like Speedfan?

    You also do not mention what case or fan size you are using. It could be without the case fan, it is your power supply that is overheating. I could not find any detailed info on the Nexus web site, nor any support site. However, it may have a temp failsafe shutdown in it.

    At any rate, if it turns out the fan must run, you might look into a quieter fan. Web sites like this may be able to help. ,

    You can Google "quiet PC" for more choices.
  2. I meant the chassis temperature. And no I'm not using Speedfan. I'm just looking at the bios(UEFI) H/W monitor.

    The case is a Silverstone LC17. The cooler I'm using is a Scythe Samurai ZZ. The case fan is pretty small, so it's no wonder that it's a little noisy, but it simply shouldn't be necessary for it to be on at all. I'm not interested in looking for a workaround by getting a quieter fan.

    As for the theory that the PSU is overheating, it seems very unlikely, as the PSU is specced for 530 watt, and it probably hasn't needed to deliver more than a 100 watt at most. Another reason I don't think the PSU is the problem is because I did a stress test later, with the fan just spinning high enough for it not to shut down, and it didn't crash then. Though, maybe it would be worth checking if the PSU is faulty. Though that wouldn't explain why more moving air would counter the problem.
  3. When I was referring to the PSU getting hot, I was not referring to load.necessarily. I was referring to the excess heat in your system being channeled out through the PSU by it's fan. If the fan is designed to be slow and quiet, it may not be able to keep up with the extra heat. I apologize for not explaining it more clearly the first time. Had not had enough coffee yet. :)
  4. Ah, well that seems quite impossible as well. I often keep my case open when i just built it. I've tested the problem, half the time with the case open. And since the case is on it side, any excess heat should neatly exit upwards out of the case.

    Also I want to add that the problem can also be circumvented by increasing the RPM of the CPU fan. That way I can keep the case fan off. But of course that leaves me with a noisy CPU cooler
  5. I would opt for replacing the case fans with inexpensive Antec Tri-cools set on low speed. This will serve two purposes. First is obviously cooling, but the second is that at low speed these fans are basically silent unless you are right on top of them. Not only would I replace the 2 rear fans, but I would add one on the side opposite the PSU(all blowing outward of course). They will also provide sort of a "white sound" buffer against the other components, including the CPU fan. And they would also provide more than adequate cooling.
  6. Changing the case fans with quieter, doesn't fix the underlying problem. Besides there is no reason for me to have better fans when the the cpu and chassis don't even get warm.
  7. Sorry, I am out of ideas.
  8. No problem. I guess I'm just going to return it and get it fixed.
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