Opteron 185 running hot

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I've suffered a few BSODs after the PC has been on for a few hours, so I
think it must be a heat issue. So I loaded up ASUS probe and it says my
Opteron 185 is running at 55 at idle. I don't know if ASUS probe is
accurate for this particular setup or not. MB is an A8N-SLI with stock AMD
HS and fan. The HS is clean and the fan is spinning at 5K RPM. Room temp. is
80 F BTW.

Any idea if PC Probe II is accurate? If so, WTF is the Opteron running so

Re: Opteron 185 running hot

Bill Stock wrote:
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1) Run CPUZ and verify your frequencies.

2) Check the core voltage in Asus Probe. Note that if Cool N' Quiet
    is enabled and set up properly on the board, that the processor would
    operate at a variety of voltage/frequency values, as a function of load.
    Thus, you may want to load up the processor with a computing task
    (cpuburn, prime95, or the like) while doing measurements. It is harder
    to do a reliable idle reading, as the program doing the reading may cause
    the FID/VID to change.

For examples of Cool N' Quiet voltage ranges, there are a couple docs here.
Min Pstate is the Vcore at idle, if Cool N' Quiet is running. Max Pstate
is the Vcore as seen when the CPU runs at full load, or if Cool N' Quiet is
disabled. The OS adjusts FID/VID, something like 30 times a second. Which
is why, watching Asus Probe take a reading once a second, is going to miss the
details. Typical values might be 1.3V at Max and 1.1V at Min, and
that helps reduce the idle power output. Similarly, the processor
may have other features (bus disconnect on HLT and the like), which
further improve idle power.


Opteron - typical Pdiss 110W full power, 49W in Min Pstate. 185 is not listed ?

An Opteron 185 uses 110W at full load. Nominal Vcore at full load is
1.3V or 1.35V. Varies from unit to unit, and may not be stamped on
the box. It is actually pretty hard to draw any conclusions from a
single voltage reading, because in fact there is a load line for the
regulator. But if your voltage was way off, you may be able to detect


For the CPU cooler to work, the computer case air temperature around
the cooler, must be low enough for good heat transfer. For example, if
room temp is 25C, a computer case or motherboard temperature of 32C or
less, would make it well cooled. If the delta to room temperature is
more than 10C, then you should work on improving your case cooling.

For example, my room temperature is 25C (I have a room temperature sensor
mounted in front of the computer, where the intake vent is). My internal
case temp is 29C. I have a 120mm fan on the back, running at a pretty good
speed. I removed the lower plastic bezel on my case, to expose more vent
space. I removed the dust filter as well. My CPU never goes over about 43C
(but it isn't as powerful as your processor).

You could change CPU coolers, but that only makes sense if the air in the
computer case is relatively cool. There are coolers with theta_R of
less than 0.20C/W . With a 110W processor running flat out, you
would expect a CPU delta_T of 0.20 * 110 = 22C above computer case
air temperature. If the case was 29V, that would leave the processor
at 29C + 22C = 51C. And that is a full load temp - at idle the delta
would drop a bit less than half, or 29C + 11C or 40C. So there is some
room for improvement.

Example of a cooler with theta_R below 0.20C/W:

The reason I'm suggesting checking frequencies and voltages, is the power
dissipated is proportional to those. F*C*V**2 at normal operating values
is listed at 110W. If the voltage is higher than the 1.3 or 1.35V nominal
values, the power dissipated goes up as the square of the voltage, so that
can have a bit of an effect.

Hope that gives a few ideas,


Re: Opteron 185 running hot

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Thanks Paul, that's an excellent reply.

Sadly, my PC bit the big one at about 10:00 pm this evening. I'm somewhat
glad that it's definitively dead, as opposed to months of BSODs. It might be
the video card, as I got pretty coloured text on the last BSOD before it
succumb. Oddly though, the UPS is also acting up now, charging and not
shutting off. So it might also be a Power Supply problem. I've also read
about the PCI-E slots dying on the A8N-SLI, so that's another possibility.

I can't boot into the BIOS at all now, the screen comes up black after it
POSTs and I hit the DEL key. If I let it continue past the POST screen, it
dies halfway through the configuration screen.

Just after I sent the first message, the CPU dropped to about 48/49 and
stayed there, no idea why. Voltage was about 1.34 BTW and the MB temp was in
the low 30s. So some better airflow will be in order, once I fix the current

Re: Opteron 185 running hot

Bill Stock wrote:

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Try powering the system, without the UPS in the path. Just in case the UPS
is no longer delivering full line voltage.

As for the current symptoms, are you saying that you see some of the BIOS
screen or you are not seeing it ? If you see some BIOS screen, then the
processor works, the PCI Express slot works, and at least the frame buffer
on the video would be working. I think a PCI Express slot failure, would
leave you with a black screen that never renders anything.

You could try plugging the video into the other slot, assuming if there is a
paddle card, it is in the x8/x8 setup.

There are some ways to kill a processor, but you'd have to be overclocking
for those to be applicable. I've read a couple descriptions, of what
appeared to be electromigration failure. I've also read of problems with
the FX series of processors, where the problem was traced to the delta
between core voltage and memory voltage. (The datasheet doesn't specify that,
but enthusiasts figured it out based on what systems were failing and what
ones weren't.)

Are you getting a burnt smell from any of your gear ? Perhaps that might hint at
a part that has failed.


Re: Opteron 185 running hot

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The UPS failed its power on test after I powered it off last night, so it's
the most likely suspect. I just moved everything off the UPS, as my router
and modem are also on the UPS. I can now get into the BIOS, but it can't
find the BOOT disk.It sees SATA 1 and SATA 2, which are my striped drive.
But it does not see SATA 3 and SATA 4. I was hoping it was a loose cable,
but that does not appear to be the case.

I'm a little pissed that the UPS might have caused the very damage it's
supposed to prevent. I had ordered a new battery for it, but I don't think I
would trust it again.

I'm not overclocking, the room temp is just too high in the summer. I would
have to go back to water cooling, which was OK, but a bit of a PITA. The
only smell is that of batteries cooking. :-(

Re: Opteron 185 running hot

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I tried moving Sata 3 and Sata 4 to the Sata 1 and Sata 2 connectors in
hopes of booting up. But then the system does not see any drives. So on the
bright side, the SATA interface seems to be OK, but the drives or PS are
fried. I'll play with the power combinations later to see which drive/PS is
fried. Although I find it unlikley that only one PS lead would be faulty.
It's likely that one or both drives on that PS connector got cooked.

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