I'm possibly being fussy or this is a sign of slow/steady board death?

[mikeymikec]

I'm inclined to go with the former, but this is an odd issue I'm seeing so I thought I'd run it by the forum.

My PC's board: ASUS M4A89GTD PRO/USB3

I've had it since about mid 2010. Until recently, it read the CPU fan speed absolutely fine, but now I'm seeing an issue every single time whereby SpeedFan (using either CPU fan sensor) and HWMonitor both intermittently show the fan speed varying between a normal reading (about 1.2k RPM) and either a reading that's double the normal reading or going up to something completely absurd like 675000. CPU temp remains stable/normal (about 30-35C). System noise level also remains normal. The chassis fan speed reading is always OK. The CPU fan speed reading jumps between normal and blatantly wrong every few seconds generally, but one time, after doing a BIOS update to the latest release, it showed a normal fan speed temp for at least a minute.

One other issue I've had (however I think I just figured that one out) relates to a DVD drive that the PC couldn't detect after a reboot, but because I have two DVD drives and one has always been iffy, I've just ordered a replacement for it.

I'm going to lose the CPU under-volting setting for now (it's a tiny undervolt, reducing the CPU voltage by 0.0625v, the maximum the board will do), just in case that inexplicably has something to do with the situation.

 

[VirtualLarry]

Do you have both fan-monitoring programs open at the same time? They can stomp on each other when it comes to reading the system's monitoring hardware, and will cause errant readings.

 

[mikeymikec]

No, I only installed SpeedFan when I noticed that HWMonitor was showing screwy readings.

 

[Ketchup]

Are you running Ai_Suite? I can't get anything else to give me good fan speed numbers.

 

[BonzaiDuck]

The suspicions already voiced are well-founded.

You can crash a stress-test with an otherwise-stable setting by running two monitor programs simultaneously.

If the ASUS AI Suite icon shows in the system tray, I've concluded that it continues to poll the sensors.

I have seen these odd readings, for example "125,000 RPM" etc. or negative temperatures, more than a few times with different systems, and they always appear when running more than one monitor program. And they are more likely to appear with double-monitoring and stress-testing, when CPU and/or RAM resources are getting scarce.

 

[mikeymikec]

I've already said that I was only trying one monitor at a time and that SpeedFan wasn't installed to begin with. I've just tried uninstalling SpeedFan and installed AISuite, but I get the same readings.

I've just checked the BIOS and it's giving equally screwy readings for the CPU fan only. The chassis fan reading remains normal.

 

[Ketchup]

So I suppose it comes down to: is it a problem with the fan, or it is a problem with the fan header?

 

[mikeymikec]

If it was a fan problem, I'd surely hear the doubling in fan speed. It's a very quiet system, which I've worked on ever since I built it to bring the noise level down.

When you say a problem with the fan header, I assume you mean the sensor?

 

[Ketchup]

If it was a fan problem, I'd surely hear the doubling in fan speed. It's a very quiet system, which I've worked on ever since I built it to bring the noise level down.

When you say a problem with the fan header, I assume you mean the sensor?

I am probably going to over-simplify this, but want to make sure we are on the same page.

Well, the temp sensor will dictate what you, the bios, or the Windows software tell the fan to spin at (unless it's a straight-up PWM fan). The power header dictates how much voltage the fan gets, and therefore how fast it will spin to reach the set destination. I have had more than a couple boards that adjusted speed correctly, but software reported speed that was ridiculous. I just assumed the fan (or the board) didn't support the type of adjustment the software was trying to read.

My opinion: if the sensors are giving you good temp numbers, I wouldn't worry too much about the fan speed numbers.

 

[mikeymikec]

I assumed that the 'header' was basically another word for the fan socket on the board.

I had another play around with this problem (only in the BIOS, I didn't bother booting Windows at all during this), and I found some interesting things:

1 - If Q-Fan for the CPU is disabled, the fan speed is read correctly (Q-Fan is also enabled for the chassis fan yet it is and has always read fine).
2 - If the fan type for the CPU fan is set to DC, the fan speed is read correctly (however the fan speeds up considerably on the standard profile).
3 - If Q-Fan for the CPU is set to manual management, the fan speed is NOT read correctly (it's normally on 'standard').
4 - I tried setting CMOS defaults through the BIOS, it didn't help. I might try doing a CMOS jumper reset job, but it seems unlikely that it will help.