[Asus P5Q motherboard] Very low CPU temps, resulting in fan stuck at low rpm

[toyo]

Hey guys. Needing help with my failing PC once again.

I'm having this problem lately with the CPU temp (not the cores, these temps are reported correctly and are into the low 40s on idle), it's most of the times detected as low as 1-5 degrees (Celsius). I did not made any changes I can remember other than replacing a faulty HDD with new SSD/HDD (but I cannot guarantee this was the start of the problem). It just started to happen (I have AIDA64 OSD running).

Important mention: the CPU sensor is not stuck when it indicates low temps, the temps go up on load, but they're 15C or so lower than normal.

This is bothering me because I use a Freezer PWM cooler set on Turbo on BIOS. The fan needs to go as high as 2500-2800 rpm to keep the CPU cool when it needed to work on the hot ambient here, but now, because the low CPU temp is detected, the fan sits lazily at 1100 rpm and the cores go up to 65C (tested with IntelBurner). What's even more annoying, is that sometimes the correct CPU was reported after a reboot (this is not happening any more - the temps are wrong for good it seems) and the fan immediately starts working correctly again, but it never lasts. Everything on the motherboard is correctly seated with Arctic MX-3. I did a fresh reseating for the Arctic cooler, but it did not help.

Additional problems I have noticed: the CHA fan is no longer detected, albeit it's working OK. A wrong DRAM reading appeared out of nowhere during my attempts to repair this issue, detecting a 2.02 V - incorrect, as the RAM sticks are working at 1.8 V.

I have also tried reflashing the BIOS to older versions, resetting CMOS, overclocking the CPU up to 3.5 GHz, everything in an attempt to get the sensor IC unstuck, but none worked.

Speedfan is not a possible resolution - I cannot control the fan on my MB with it.

Is there any way I can "reset" the sensor to its former, correct behaviour? Please help, I'm getting desperate here, as the only way I can tackle more demanding tasks other than browsing is to disable the Q-FAN BIOS option and let the fan always work at 2700 rpm - it's like having a blowdryer in your ears all the time.

Thank you!

E7200 2.53 GHz, Asus P5Q (2209 BIOS), Kingston 2x2GB DDR2-800 5-5-5-18 1.8v, Asus EAH4850 512MB 625/993, 23" Fujitsu-Siemens LSL 3230T, Corsair Extreme SSD x64/Samsung Spinpoint F3EG 1TB SATA-II, Windows 7 SP1 Ultimate x64

2.53 GHz, stock:

3.16 GHz, OC:

DRAM wrong entry:

[mara-]

I just read that guy managed to un-stick the sensor by raising the CPU voltage. Now, I don't know how much would be safe for you CPU.

Cheers ;)

[toyo]

Hehe, that's just what I did (with no results). I have since taken out the mobo and just gave every chip a few knocks, and then cleared the CMOS again - everything went back to normal - at least for a day or so.

Now, the temps are slightly going down again... 18C on idle right now (should be like 25-30C).

Asus support emailed me suggesting to RMA the MB at the place I bought it. Sadly, that place is no more, as it was a former client which is now bankrupt and probably on the run from the banks with what he has left of his money --> he cannot be found :) I've sent them back an email to try to RMA it directly with Asus somehow. I have no idea what can they offer me, as LGA775 mobos are no longer in production...

I'm pretty annoyed at the thought I will remain PC-less, but I know that this Winbond chip failing is just the first step - slowly, the whole MB will fail, I've been through such progressive hardware deaths before...

[mara-]

Wait a minute. Motherboard should not be the issue here. Your CPU is. CPU has it's sensors which are probably faulty somehow, not motherboard.

Cheers ;)

[Maxhedroom]

The 32nm Wolfsdale cpus were known for sticking temp sensors...worse on the Core2 Duos than the Qauds...not sure what your running. I hope things hold out for you tho... :mellow:

[mara-]

You mean 45 nm Wolfdale? And yes, it's seems they have a problem. I have E8400 and when I stress it, difference between cores can be 5-6 C, but it least they are working. And E7200 is also Wolfdale.

Cheers ;)

[Maxhedroom]

Oops...yeah meant 45nm. My 2nd pc is a E8400 on an Asus P5K-E WiFi mobo. Didn't stick much, all I had to do was correct Tjmax in real temp to 100c and it gets close enuff for me. It's also using a 120mm Thermalright cooler with a 2,500 rpm fan...ofc that helps a little.... :hehe:

[toyo]

I said "CPU temp" not "core temp" ;) The CPU works just fine, including the core temps (read from the Intel diodes).

The CPU temp, read from the motherboard Winbond chip, is faulty. This temp is all important, since the CPU PWM fan depends on it to perform correctly. In my case this temp is very low, so the CPU fan thinks the CPU is cold even under heavy load and fails to spin faster to compensate for the temp delta. This leads to overheating and crashes, obviously.

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Oh well, I got a negative response from Asus support, they won't let me RMA in the UK - or anywhere else I think. Additionally, LGA775 boards are no longer manufactured, just as I thought. I just wrote a pretty harsh (but still polite) reply trying to negotiate a deal somehow, but I doubt it will achieve any effect - other than to make me look like a dickhead.

I'm just so very tired of failing hardware, I only want these things to work as advertised, but no, this is not possible. The economics of the game dictate that hardware that lives to long might be detrimental to profits, so it's not much of a surprise to see all these components just giving up after a short time, or even DOA.

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I think it might be the PSU (3 yrs old 450 W Delux crap)?!? Can somebody give me a 2nd opinion on that?

I'm saying this because I have OC-ed the NB/FSB termination to 1.20 V and CPU to 3.5 GHz and the CPU temp was again normally correlated to core temp.

Maybe my PSU is failing and it undervolts my MB... dunno.

Edit: Overvolting the NB and FSB termination is enough to get the sensor unstuck :huh: So now both are at 1.20 V. I'll try bringing them down later...

2nd Edit: Only the NB is @1.12 V. This seems to keep the CPU temp happy. For how long? One can only guess, lol

[mara-]

Well, can you borrow PSU from somebody to test?

Cheers ;)

[toyo]

Cheers mara- :P

I don't think I have where to buy a PSU. I have a few older ones, but none have the SATA power connectors that I need. Will probably have to buy another very cheap crap PSU soon, I tried to avoid that until I could buy a good one, but seems it's rather unavoidable.

For now, I'll stick with the slight NB 1.12 V OC. Like I have other choices :lol:

[Maxhedroom]

If worse comes to worse, you can get 12v molex to sata power adapters for like $2 each online...of course you'll get screwed on shipping... :wedgie:

[toyo]

I'm almost sure I have some of those. I should search for them the next time I decide to clean the house :) Keep them handy just in case the PSU fails.

[toyo]

OK, I'm 90% it's the PSU. I guess now I only have to wait until I can get a new one.

How do I know? I had to put my videocard (which is most probably the hungriest component) through some serious work and each time it's working at 100% capacity, the CPU temp drops. I stop the GPU workload, the CPU temp gets back to normal. So I guess that particular Winbond sensor chip is not getting enough electricity. At worst, undervolting can cause the instability, but not the failure of components, so I think I'll have to live with it... :mellow: