XPS Desktops

Last reply by 07-21-2021 Solved
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2 Jasper
2 Jasper

XPS 8940, Better 3rd party cooler

Hello there

I would greatly appreciate any help to find a new/better 3rd party cooler for my XPS 8940. It came with the thin and small stock cooler and is overheating the whole time. I got a i9-10900 processor with 128 GB of RAM and I need this computer to generate some GIS layers. These jobs take 2-4 hrs every time and I can see that the processor is throttling or C° 97+ all the time.

I tried the Noctua 15S but the problem is there is no space for the bracket under the motherboard. The stock fan screws directly into the chassis from above.

Thank you very much

Replies (929)


I am doing what you have done; exactly. I have my fans on order from Amazon. 
you state; “Just plug into the same fan headers the standard ones (fans) do, works perfect” - these headers control the fan speed, so I’m assuming your fans are running slow - is this true? If so, I don’t see how the CPU temps are so low? It was my understanding that the fans needed to run faster to get the air moving better over the CPU heat sink. Can you help me to understand?  Thanks. Scott



Fans are only running slow when the pc is idling. The fans ramp up and down with temps, just like the standard fans, except the noctua’s do it a lot quieter due to lower peak rpm.  The temps are running much lower due to better flow from the new fans and the massive heat sink the nh-u9s has in comparison to the stock cooler. 




Thanks. Hope to get my fans next week. 

in order for the fans to speed up some thermal set-point is reached, then the fans go faster. This ‘set-point’ is not changed, so the CPU must be getting upwards of 95F to make the fans go faster. I’ll soon see. Take care. 



Correct. The thermal set point is managed in the bios, which is evidently locked down in these XPS 8940’s. I’m not sure what temp that is, but I guess you could use speedfan or similar to check at what point the fan rpm’s rise in relation to temp (NZXT CAM doesn’t show my cpu fan speed). You could also look into using the na-fc1 if you want to take a bit more control of fan speeds manually. Stock fan curves seem to be working well for me though. 
See below. 





I used fortnite as an example as it seemed to run hotter than other games even at low cpu load.


Pictures did not come through. I’ll try what you have done and if I’m not happy I’ll get the controller. I think that’s the way to go but I’ll try this first. I know excessive heat is a killer for electronics. It’s winter in Colorado so I’m not worried about excessive heat (ambient room temp is 65), but in the summer, it’ll be deadly for the CPU and possibly memory. The fans I have installed over my open chassis keeps my CPU temp at 75-78 now. I’d like to get a few nice games at some point but mostly do video editing which can be CPU intensive. I’m in no rush but I want my system running cool when I’m done. 


Bugger about the pics. It shows cpu temps at 88 degrees celcius before the upgrade and 59 celsius after, at 23 percent load. And I’m in Australia in the middle of summer at the moment. 


That’s a great differential!! I’ll hope for similar. Fingers crossed. Thanks. 


As you have have read, cLiinKz plugged his Noctua fans into the 4 pin headers on the motherboard, replacing the old fans (see post 1-23-2021 06:29 PM). This, of course, will run the fans at a variable speed controlled by the temperature (thermistor controlling the PWM width or similar) of the CPU and inside the chassis (exhaust fan). His before and after temp readings were 88F (standard 8940 – no mods, fan on slow speed) and 59F (after installing the Noctua fans and just plugging into the existing headers; assume the fan speed is still low). What this indicates is that the nh-u9s heat sink is so large (compared to the original one) this, along with the low RPM of the fan, is enough to keep the CPU temp down to the 59 F. I am doing the same thing and hope my results will be similar as if I can run the CPU at 60 degrees F, I’d be happy. This will not cause any BIOS boot errors as there are still 2 PWM fans plugged into the motherboard.

There seems to be two options when installing new fans;

1) to use a spare SATA cable to provide power to the fans, which will run the fans at the max speed but it’s unclear to me how this connection would work as I would need a cable from the SATA cable to the 4 pin PWM fan connector. This cable would only supply power to the fan (can’t be a 4 pin PWM connection – unless someone can tell me how this connects). This will also cause a BIOS error on boot as the fans are not connected to the motherboard header(s). It might be possible to keep the original fans in the system and install 2 new 12V fans elsewhere in the chassis – but I haven’t seen anyone doing this.

2) The most reasonable connection is to use the Noctua speed control kit (NA-FC1) which plugs into the 2 motherboard fan headers, and into the fans. Speed adjustment is then controlled by the Noctua box manually. This gives no BIOS error.

If anyone has done #1 above, I don’t think you used a 4 pin PWM fan – you used a straight 12V fan and just connected it to the SATA cable for power. The fan runs fast – at its max speed / noise. You will also get a Boot error if you disconnected the MB fans. If this is not correct, I’d like to get more details of how you did this.




Just to clarify, my temps are in Celsius not Fahrenheit. 


Thanks for the correction... you mention 88C before the new heat sink and fans; the max Tjunction temp of the i7 10700 is 100C, so you were getting close. I'm glad you made the change.. as I will soon. I should have the parts this Thursday. 

If Speccy is correct, reading temps, it shows my CPU at 76F (24.5C) up to 90F (32.2C). This is with the side off, laying on it's side as shown in my past post (although that was an HP computer, it's the same configuration). Getting to 88C seems very warm compared to my readings.. but I'm not stressing my system at all. 


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