XPS 8940, CPU thermals, coolers, and fan curves

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Thanks! I totally missed the whole last part of that thread! Just ordered  the NH-D9L and some screws

Would you happen to know anything about accessing the fan curves?

@KeyboardB    Would you happen to know anything about accessing the fan curves?

There might be a 3rd party app somewhere . . . but honestly, I don't think the fan curves can be accessed in the XPS models. Peeps would be turning the fans way down for quiet and end up frying some components . . . and then Dell would have to replace those under warranty. I think that is why it would be a no-go.

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Update for future people like me: I installed the NH-U9S yesterday and started some stress testing on it. Unfortunately I did not record exact temperatures before the replacement, however I do have a general idea of how they compare.

Parts: Noctua NH-U9S, XPS 8940, 16mm M3 screws.

Installation: Installation was easy even though I had never installed a cpu cooler before. The only issue was that my M3 screws came with both a normal washer and a lock washer. The lock washer almost made it too short, so I would recommend not getting lock washers.

During the install I also moved my HDD to the top cage and removed the front drive cage entirely to maximize airflow.

Here are some pics of the installation and final configuration

Results:

Idle temperatures dropped roughly 10-15c from mid 50's or 60's to about 45c. While stress testing using Cinebench r20 temperatures reached 80c, down from 90. Folding@home at full bore did get up to the 99c range, however, it took a lot longer for that to happen. Taking the sidepanel off dropped those temperatures down by around 10c. Frequency under load still sits at 4.66ghz as before, but under a light load approach the 5ghz mark that it didn't before. A lot more air gets moved through the case now so it is a little bit louder than it was with no airflow, however it is just air movement noise, no fan whir or mechanical noise anymore.

Overall, I'm not sure it was worth the $60 some odd dollars I spent on it. Temperatures are better, but are certainly not where I would like them to be, especially under load. 90c is uncomfortably hot. Perhaps adding another fan to the cooler and somehow strapping one to the front of the case would improve things, but I'm $80 in at this point, between the cooler and the rear case fan, and not exactly thrilled with the results. That being said, my XPS did come with the larger tower cooler so I guess what did I expect?

Final thoughts: Airflow is the limiting factor. The way the front intakes are designed and the way the graphics card is positioned limits airflow to the CPU at the best of times and starves it when the GPU is running. Dell could have and should have designed places for intake fans, or, at least, more than one exhaust fan. Do better Dell.

@KeyboardB     I installed the NH-U9S yesterday . . .

I'm confused . . .

from Noctua site

NH-U9S

NH-D9L

Oh excuse me, I typed that edit up just after I woke up. It was the NH-D9L that I installed. Thanks for catching that!

@KeyboardB    It was the NH-D9L that I installed.

The new cooler looks great . . . and it looks like you did a good job installing . . . with good temperature results.  You mentioned possibly adding a second fan to the CPU cooler . . . did the NH-D9L come with a set of clips for a second fan . . . or would that be a custom mod?

Noctua sells it with only one fan in the box, but it uses the same 92mm NF-A9 fan that I used to replace the case fan and it does come with two sets of fan clips. Drop $16 on another fan and it's plug-and-play.

The NF-A9 comes with a Y-splitter so both could run off the CPU fan header. I am not certain if a second fan would work better in a push or pull orientation or if both fans would go on the outside of the heatsink instead of having one in the middle, but I'm sure there's documentation on that somewhere.

Hi, @KeyboardB ,

"I am not certain if a second fan would work better in a push or pull orientation or if both fans would go on the outside of the heatsink instead of having one in the middle"

Just my opinion, but I think the practicalities of space might dictate which side you locate the extra Fan on (without trying to state the obvious, I'm assuming that the additional Fan will be installed so its Flow is the same as the Cooler's existing Fan)!

NOTE:- I don't have a XPS8940, hence I'm just looking at your Photos (which are good), it is not obvious that you have the Space to add a 2nd Fan without clashing with the Case Fan (on one side) or the Memory (on the other)!

Good luck in your endeavours!

I believe you are correct in your assessment on all counts which makes my wallet happy

Thanks!

@KeyboardB    I believe you are correct in your assessment on all counts which makes my wallet happy 

I'm not meaning to stress your wallet in any way        but . . . it is unfortunate that you did not install the Noctua NH-U9S you mentioned earlier . . . with dual fan capability. Your 125 watt TDP processor is one that could actually benefit from the increased air flow.  If your temps are looking good based on your usage regime . . . no need to modify.  Besides . . . even with the NH-U9S, you may run into the same space issues mentioned by  @John-Jay   with dual fans . . . I'm not sure if 33mm clears the RAM.

I just put the Noctua NH-U9S in mine.  XPS 8940 with a 10700 and 2060 Super. Even being lesser of a CPU/GPU than yours, it was running way too hot! It had the stock crappy intel GPU cooler (not the k/f version).

I also have the Noctua NF-A9 92mm in the rear exhaust combined with Noctua NF12x15 in the front upper portion (I moved the hard drive to the top and removed the cage). The fans alone netted me maybe 2-5C, not enough! Both are run of the same header. I tried the NF12 off of sata power using the LNA, but the noise of the air movement into the little holes was too loud... I am going to cut out the small partition on the plastic to the bottom vents later and try the NF12 again off of sata /w LNA. And don't put the stock 80mm fan in the front lower position as it is way too loud! I may put another NF-A9 there later. 

.... The best upgrade was the cooler. That netted me anywhere from down 10c (idle) - in low to mid 30s now, used to be low to mid 40's, down 30C gaming - in low to mid 60s, used to hit over 90 peaks (grr!!!), and only hitting 82-85 in benchmark testing (before the CPU cooler, it would thermal throttle).

I can post pictures later. I chose the U9S over the D9L after reading the reviews with more of them favoring the U9S.... plus it has more heat pipes and more fin area. The new cooler and fans are also way quieter than stock. I can't even tell if/when they RPM up.

@kanadian-kaos    I just put the Noctua NH-U9S in mine.

That is great that your temps are under control. Looking forward to some photos . . . much appreciated. Can you tell if it would be possible to add the second fan shown in the schematic in the post up-thread . . . or would the fan be obstructed by the RAM modules?