Should I Worry About Voltages?

jimmy512 · 08-04-2008, 02:55 PM

I just set up another arch install on my system, after trashing my old one. While setting up fan speed controls, I was using sensors to check that the cpu and chipset wasn't overheating. No problems there, but what I did notice was several alarms next to specific voltages read out. Heres some nice output for you:

Quote:

k8temp-pci-00c3
Adapter: PCI adapter
Core0 Temp: +33.0°C

it8712-isa-0290
Adapter: ISA adapter
VCore 1: +1.10 V (min = +0.00 V, max = +4.08 V)
VCore 2: +1.55 V (min = +1.28 V, max = +1.68 V)
+3.3V: +3.30 V (min = +2.78 V, max = +3.78 V)
+5V: +6.10 V (min = +4.49 V, max = +5.48 V) ALARM
+12V: +11.97 V (min = +9.98 V, max = +13.95 V)
-12V: -1.59 V (min = -22.94 V, max = -17.05 V) ALARM
-5V: -2.42 V (min = -9.14 V, max = -7.75 V) ALARM
Stdby: +5.13 V (min = +4.49 V, max = +5.48 V)
VBat: +3.14 V
fan1: 0 RPM (min = 664 RPM, div = 8)
fan2: 5625 RPM (min = 664 RPM, div = 8)
fan3: 2311 RPM (min = 664 RPM, div = 8)
M/B Temp: +12.0°C (low = +0.0°C, high = +73.0°C) sensor = transistor
CPU Temp: +42.0°C (low = +0.0°C, high = +73.0°C) sensor = transistor
Temp3: +55.0°C (low = +0.0°C, high = +73.0°C) sensor = transistor
cpu0_vid: +1.100 V

So basically what I am worried about is this:

Quote:

+5V: +6.10 V (min = +4.49 V, max = +5.48 V) ALARM
-12V: -1.59 V (min = -22.94 V, max = -17.05 V) ALARM
-5V: -2.42 V (min = -9.14 V, max = -7.75 V) ALARM

There are no noticable symptoms of this at the moment, but I am worried that I might be wrecking something, though I would have thought that this would only happen at a voltage that is too high. Anyway, the system has been running for 7 hrs 30 mins now, with no problems. Am I just paranoid, or should I look at replacing my power supply for something a bit more expensive? It is my second one this year (the first went with a bang).

makuyl · 08-04-2008, 03:42 PM

Probably the software not reading hardware sensors correctly. Check if you have voltage data in the bios, that should be correct.

jiml8 · 08-05-2008, 02:41 AM

Tweaking sensors is a real PITA. If you read the config files, you'll find all kinds of algorithms for this board and for that board, and what it comes down to is that sensors sucks.

If you are really concerned, get a multimeter that you know is calibrated, and use it to actually measure the voltages that are reaching the motherboard. Write the values down and compare with sensors. You then will know how to tweak the algorithms so you get the right numbers.

Better, I think, is just to assume that since your system is working reliably all voltages are within tolerance. So what you do is watch sensors periodically looking for changes. Skip the negative voltage values - those are garbage in your output. Pay attention to the Vcore voltages, the 3.3, the 5, and the 12 volt indications. You will see them move around in normal use by perhaps as much as 3% of their value (particularly on the 5 V line) but if you see a steady drift over time, or if you start to see wider swings, then you might start considering that there is a problem coming.

jimmy512 · 08-05-2008, 05:47 AM

Okay, thanks for the info. I'll have a look in the bios too, but there is probably nothing wrong with it.