Hi @Jamieson Olsen ,

Try roll back to A13 while it helps fixing lots of problems on mine.

Tried rolling back to BIOS version A13. The front "PCI" fan is still running too fast (1800 rpm) and loud after a cold reboot.

One thing I noticed when reading the service manual is that my T5600 is missing the ambient temperature sensor (Dell part number 8K4WM). Could this missing sensor be causing the fan controller to ramp up to the higher speed?

There also a note on page #12 of the owner's manual that "The thermal sensor is an optional component and your computer may not ship with it". My T5600 don't have it either, and I didn't experience the mentioned high speed fan issue.

Ever perform a BIOS reset after upgrade/fallback? No basis but worth to try.

I still have BIOS A13 loaded and will try to do a [reset to defaults] followed by a cold boot.

Another potential clue: speedfan shows one fan sensor reporting back 52,000 rpm. Clearly this is either a bad fan sensor or an unused input into the fan control chip. Can anyone with a T5600 confirm this reading?

speedfan snapshot

Fan1=CPU1, Fan2=front fan "mem", Fan3=front fan "mem", Fan4=front fan "pci", Fan5=???

Pwm2=???, Pwm3=Fan2 control, Pwm4=Fan3 control, Pwm5=Fan4 control, Pwm6=???

Installed a shorting jumper for 10 seconds to clear the CMOS memory and powered up. The front fan speeds are unchanged: at power up the two mem fans are ~900 rpm and the pci fan is ~1800 rpm. If I run the speedfan utility I can set the pwm3,4,5 channels to zero, then all three front fans slow to 800 rpm and that's pretty quiet.

As I don't see any improvement with the earlier A13 BIOS I'll go back to the current A18 version.

A warning about the SpeedFan utility. Messing with the PWM controls seems to put the embedded fan controller (EC) into a bad state where the fan speed is FIXED and no longer responds to temperatures. In particular, the CPU fan stays at 1000 rpm and when under full load the CPU temperature keeps climbing until it begins to hit the upper thermal limit and throttle down.

A suggestion that might be worth a try:  Download HWiNFO (HardWare info).

Another petitioner went through everything much like you did - Made sure fans and computer were clean; replaced CMOS battery; replaced thermal paste; and I'm sure there was more.  After downloading HWiNFO, the fans ran normally and she had no complaints about any of the fans being on a fixed speed.

Interesting, this almost exactly mirrors my experience on my T3600, although my problem seems to be caused by SpeedFan instead of a BIOS update. In hindsight, swapping system fan 2 and 3 would have solved my problem.

I apologize if I hijack  your thread, but they show similitude.

The T3600 has the latest A17A BIOS,  E5-1660 CPU and 16Gb ECC memory. The automatic Environmental Control was working fine. I then installed an AMD RX580 (Powercolor RedDe*il) in the blue graphics PCIe-16 slot (had to remove the steel bar attached to the cover).

In games the CPU would hold a temp of around 80 c with CPU fan at ca 3500 rpm, with case fan 1 and 2  2500 rpm (give and take). However the GPU kept building up heat towards 90 c with the GPU fan at MAX whilst the case fan 3 stayed at idle (850-1000 rpm).  This seems to make the GPU 'regurgitate' its own heat with most of the air from case fan 1 and 2 being expelled through the CPU/top rear ventilation of the case This is aggravated by the size of the GPU almost forming a partition in the case.

To remedy that I tried HWiNFO64, but it could not give me control over case fan 3.

I then tried SpeedFan which gave me control, but would only do idle/max so I decided to uninstall. 

Afterwards the case fans would only stay around 1000rpm. The  CPU fan 1000 rpm and sometimes follow the automatic profile.

I've tried BIOS refresh, WIN10 refresh, disc repair, reinstalled chip and various drivers to no avail. It only remains to do a completely fresh install.

Now when needed I use HWiNFO64. However the biggest problem is that some times the CPU variable control will work just to suddenly stop at 1000 rpm causing temperatures to get well above 90 c and secondly that the on/off of the fans is annoying.

I should add that my PSU speed has shown around 53000 fixed on both HWiNFO64 and SpeedFan. 

This may not add anything towards a solution, but might add info to solve the problem.

My system started having issues with the front fan speeds out of the blue. The current setup has two gpu installed. I figured out that when I disconnect one of them, the fan speeds return to normal. Is there any sensor on the GPU that controls the case fan speeds? Thank you very much!

What GPU's do you have?  Another is having a similar issue:  https://www.dell.com/community/Precision-Fixed-Workstations/T3500-Full-throttle-case-fans-since-Quadro-K4000-upgrade/td-p/7347834

I have a GT 710 as my main GPU and a 1080Ti as a secondary. When I remove the 1080Ti the fan speed drops back to normal. It is very weird, because this setup was working for more than a year without any issue...

Hi @apath ,

Not a sensor on GPU to control chassis fan speed but temperature detected on GPU which affect overall temperature of the whole system may leads to high fan speed.

Several troubleshooting steps you can do:

- Observe when high fan speed exist,

• Right on power-on - likely to be hardware problem
• During POST - likely to be driver problem
• When Windows loaded up - likely to be software problem 

- Check if any hardware / software / BIOS changes recently. If yes, fall back and see if problem still.

- Install tools like Speecy to keep monitoring on temperature level.

- Try to boot with a single GPU on varies PCIe slots in order to narrow down possible causes leaded by defected GPU or PCIe slot.

P.S. Curious to me that why you need an entry level GT710 to work with a powerful GTX1080ti?

Thanks for the feedback!  Yah, 96°F can be a bit warm for a computer.  It doesn't sound like you have air conditioning where you are.