XPS 8940, Better 3rd party cooler

I looked hard in the BIOS and found no fan speed control.. .can you report different? I'd sure like to boost fan speed in BIOS and check the temps. I know on some Dell laptops you can do this - basically it turns off the PWM and runs the fan at full speed. I have ordered the Notcua fans and controller. However, Dell should put fan control in their BIOS.. with all the posts around here about CPU's running hot - it would be a wise more on their part. 

sc

cLiinKz;

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

@Colorado_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. 

@Colorado_scott 

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. 

Before

After

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. 

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

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. 

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.

Thanks

Scott

It does seem very warm compared to yours. Your temps are extremely low! Mine doesn’t even idle as low as 24.5C (76F)  

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. 

Scott

This is interesting to me. My ambient temp is 67F in my office (right now). CPU Temp is 80F (27C). I've got the heater on as it's 25F outside.. burr. I don't get the difference. I've only got the email program going, no background tasks that I know of. I did notice my system cooled down when I took the side off, with the open side facing up exposed to the ambient air - and that might of been 10F difference or so. Hey, you have yours in a good place. I would not worry.

*** Did the Noctua fan kit come with heat sink compound? *** I was looking to buy some (good stuff) but it looks like on the box, it shows the compound. 

I was reading that some apply the thermal paste wrong = the CPU gets hotter.. it's not rocket science but someone did write about this and he corrected it with a new application of thermal paste. Just FYI..

(this was not the article, but similar)

Intel Core i7-10700 2.9 GHz HIGH Temps Issue (stock cooling)...max safe operating temp under prolonged load? Please see pics...I'm thinking this might... - Intel Community

sc

Yeah the thermal paste comes with the cooler kit, and Noctua’ is said to be one of the good ones. 
Yeah I did my research about applying the paste, I have no doubts it’s working well with the grain of rice method. 
Are you sure your temps aren’t in Celsius? As they are way below everyone else’s on this thread..

I wouldn’t even worry about the cooler if my cpu was running that cold. 

I’m not sure of anything Speccy reports any more. I’ve only been using the program for a few days and not sure of what issues exist.  It’s been wrong (GTX 1660 on board memory), or I did not understand what I was reading (memory frequency reported at 1423, not 2933; the reading was 1/2 apparently due to Speccy not reading DDR correctly).  There is a toggle in Speccy for C/F and the temps I wrote are based on this. I did not convert C to F or visa versa. If Speccy is wrong there too then the information I reported is wrong also. 

Great on the thermal paste. Yes, I read to that Noctua is good too 

Scott