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onefortheroad_57e1bb
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February 5th, 2013 00:00
Optiplex 780 BIOS Fan Control issue
Hi,
I have an Optiplex 780 SFF desktop, and I have kept the BIOS firmware up to date, now running A14.
It's running a Q9550 CPU. Win7 64.
Ever since owning, I have noticed an issue with the CPU fan control. After the computer resumes from S3 Sleep, the fan controller logic seems broken in a bad way. Only after S3 resume, if I run 100% CPU for an extended period (possibly a few minutes), the fan does not spin up to adequate rpm and the CPU gets very hot, > 90 degrees.
However, after a normal warm restart of the computer, the issue goes away. The CPU fan speeds up properly and keeps the CPU from overheating - highest core temp around 72.
The cooling issue only appears only after resume, not boot.
Anyone able to test this?
thanks!
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onefortheroad_57e1bb
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Posted April 3rd, 2015 00:00
hi Pavel,
Yes I still have the issue 2 years later. I have now disabled all sleep functionality and just use hibernate instead, which is less convenient as I can't use USB to wake up. However this is preferable to having the entire CPU cooling system not working under load.
How do we get Dell to test this?
Pavel Kolotilov
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Posted April 16th, 2015 04:00
Hello,
I read through the Dell support documents and did not find anything similar there.
I will try to use the normal Dell way through their site, but the problem is that I got the computer from other people as a gift and I changed the original configurations quite a bit also. So, I do not know if it will work or I have to do the transfer of ownership first.Clearly it is a bios issue. But I am not sure if Dell will want to do anything for the systems which is 6 years old.
Cheers,Pavel
The latest version of BIOS for the 780 is A15.
I don't know if any of the 780 BIOS versions fixes this issue, but fixes are cumulative. So if this was addressed in an earlier version, A15 should also have the fix too.
Be sure to read/follow the instructions carefully to update BIOS, if that's what you want to do. There's always a (small) chance that the update will fail and brick the motherboard... And as I said, no promises that A15 fixes this fan issue.
That's an interesting problem. I recently acquired a Dell Vostro 400 with an E8500 processor. It works perfectly with the original BIOS and with the newest one which the Dell site installed automatically. Using the CPUID HWMonitor, the core temps are around 45C or less. My GPU runs around the same temp but ran around 60C in my old computer. Another poster had all kinds of fan issues when changing the CPU in his Vostro400. I thought about swapping to the Q9550 but single threads actually run faster with the E8500 so the cost is hardly worth it. Besides, I don't need these problems.
Good Luck.
onefortheroad_57e1bb
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Posted April 16th, 2015 23:00
Thanks.. I can confirm the issue is still present in A15, which came out 6 months after I started this thread.Pavel Kolotilov
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Posted April 17th, 2015 01:00
Hi everyone. I am really pleased that this problem caught the eye of many people :-)
I also confirm that it is present at A15, as I use it since the beginning.I do not think it is present on all Dell machines (otherwise we would hear about it already). I would rather think it is limited to optiplex 780 or maybe some other Optiplex as well. So I am not sure it affects Vostro 400.
Also I cannot say anything about the processor model. Before installing Q9550 I used E8400 and I never noticed that issue. But of course, I never looked at the temperature monitors when I was using E8400 and that processor runs much cooler (65W of E8400 vs 95W of Q9550). And I remember that with E8400 the fan was suspiciously quiet all the time.
So, bottom line: I cannot confirm that this issue did not happen with E8400.
Cheers,
Pavel
I just tested my vostro400 w/E8500. I used the HeavyLoad stress test. Tried with both S1 & S3 configurations after sleep. CPU maxed at <55C as did the GPU. Fan0 stayed in a range 1634-1648. Fan2 range 1184-1194. I checked elsewhere. Quads run hotter. One person said the Intel max spec is around 71C. You could try a larger CPU fan and heat-sink w/good heat-sink paste. (I found automotive never-seize also works well. Dielectric grease works poorly even though some people use it.) Real heat-sink compound is expensive and often hard to get locally.
Hope this helps.
Sometimes a corrupted (or outdated) video card driver can cause CPU fan issues. So consider updating the video driver to latest version available for the card and your version of Windows.
Look on either the AMD or NVidia site for drivers, depending on which video card you have, or check the Intel site if you don't have an add-in video card and only use onboard Intel Graphics.
Pavel Kolotilov
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Posted April 17th, 2015 14:00
Lulu Ford, fan is working all right. I just keeps on minimum speed after suspend and does not react on the rising temperature of the processor. It is a fan control problem, not fan mechanical problem. Also, in my machine CPU fan is the part of the case, I do not know if I even can change it or not.
Red limit is a individual characteristic of each processor and is posted on the Ark site. For q9550 it is 71.4C. There is also TJ max, which is 100. So, I guess the real red limit is around 85-90C. I work a lot with HD Video, so I constatly run on the 100% of all of 4 cores during long periods of time. Temperature often goes higher than 71C, sometimes up to 75. But it does not seem to be a big problem. That one time when fan did not spin up after suspend, temp was at 80-82 during half an hour, but I survived :-)
I use the newest video drivers, so the problem is probably not there.Cheers,
Pavel

Pavel Kolotilov
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Posted March 31st, 2015 13:00
Hi,
I have exactly the same problem! Though did not realize that it was happening after the sleep, but now I can see that in my computer the fan spin failure always happened after "Wake up". Because I could not predict when the failure would happened I had to install all kinds of hardware monitors to warn me when overheating was happening :-(
I understand that I am answering you 2 year later, so I am wondering if you managed to solve this?
My machine:
Dell Optiplex 780, firmware A15, Core 2 Quad Q9550, Win7 64
In the meantime I will probably switch off SLEEP[ function.
Cheers,
Pavel