Question What is correct fan speed for Dell XPS 8100? Why did my fan slow down?

Mar 13, 2020
Hello everyone,
I own a Dell XPS studio 8100 series desktop w /an I7 chip and Windows 7 64-bit and believe there is a problem with the PC's fan. The other day I noticed the PC was very quiet, there was no sound coming from the PC at all, I thought the PC had gone into sleep mode but it hadn't, the system was active. I downloaded SpeedFan, and the output is listed below:
Fan 1:912 RPM
Fan2: 925 RPM

Temp1:261 F
Temp2: 72F
Temp3: -53F

I'm not familiar with this application, I'm assuming Temp1 is the CPUs temperature? I googled normal operating temperature for an Intel I7 chip and it's listed at 149°F under a full load. A friend checked the PC and said he could feel air blowing out of the back (disabled, can't do it myself) near the fan but 912 RPM seems very slow. I followed the instructions at
and was able to increase the fan speed to 4470 RPM and the PC now sounds like it used to, maybe a bit louder. Thing is, the Temp1 reading is still 261°F, and the core0 through core3 temperatures are changing from 93°F to 105°F. I believe the core zero temperature reached as high as 120°F before I increased the fan speed. So, my question is how did my fan speed get changed on its own? This type of thing never happened in the 10 years since I've owned this PC. What are the correct case and CPU fan speeds for this PC? I tried searching Google but couldn't find it listed. I used SpeedFan to set both fan1 and fan2 to 100% speed, is that okay for them to be running that speed 24/7? Thanks in advance for any info you can provide!



Jun 15, 2017
i dont do F, so i have no context as to what 150 degress is
but, you should set the fan CURVE, not constent speed, for a level you are comfortable with.

the cpu temps you should worry about are cores 0-3.
if they are under 95 (CELSIUS NOT FARENHEIT) you should be fine.
adjust the fan curve to your liking
i have the fans go to 100% only when the highest core temp is 85C, 70-85C at 65% fan speed and anything lower just 30%.
If the chipset drivers are installed, (not so!)oddly enough the fan will ramp upward in speed commensurate with heat production....(all normal...!)

Not much advantage blowing at 90% max RPMs when hovering near only 800 MHz during Notepad operations...
Windows updates can also mess with fan settings. I typically set my fan settings in bios to be at 100%--this way you never have heat problems. I've seen fans not ramp up and damage systems--not worth it imo. Floor the fan and never worry. 🆒