XPS 8950, three Noctua fans cooling experience

Question

I recently purchased an XPS 8950 system with an i7-12700K and an RTX 3080 ti. I ordered the liquid cooling for the CPU.

Based on my initial testing, the CPU does not thermal throttle (i.e., it does not reach 100*C) during prolonged (5+ minutes) stress testing in Intel XTU when running without over-clocking.

For GPU stress testing, I am using the benchmark test in Cyberpunk 2077 with the graphics set to 4K ultra with ray tracing enabled (for which the system averages about 55 FPS). Running that test, the "hot spot" as reported by GPU-z gets to 88*C. I suspect there is some amount of thermal throttling at that temperature as once it gets there, it does not go any higher regardless of graphic activity and regardless of how hot the GPU was before starting the test.

I added an additional 120mm front fan and 2 92mm fans on the side panel. These are all Noctua fans and they are running off of Noctua's fan controller powered by a SATA connector. I did not want to annoy the Dell BIOS by connecting to a motherboard fan header since that often results in a BIOS error on boot up.

With the addition of these fans, I have observed the following results. Note that I set the fan speed with the Noctua controller so that I can hear the fans, but they are not annoyingly loud. First, Intel XT in automatic mode provides a mild overclock and with stress testing there is still no thermal throttling although there is power throttling (but this is not temperature related).

Second, the GPU heats up much more slowly. While it does still reach 88*C, it take 3 or 4 consecutive runs of the Cyberpunk 2077 benchmark before reaching this temperature. Prior to the additional fans, the GPU hit 88*C on the very first benchmark run.

My conclusion is that the factory liquid cooling is adequate at least up to the i7-12700K level (I don't know how the 12900K behaves), but some extra cooling helps for overclocking. Separately, the GPU could use some better cooling. From what I have read, the Dell version of the 3080 ti runs hotter than several of the competing 3080 ti boards. Thus, having some extra fans does help at least a bit when pushing the GPU to its limits.

As a side note, the fan install was very easy and did not require any additional Dell hardware. The fans come with rubber mounting plugs that fit perfectly in the various mounting points on the Dell case.

Let me know if you have any questions.

Lime21 · Answer

Thanks for sharing what you did and tested! Did you use Noctua A12 and A9s?

Did the CPU temps increase when added side GPU cooling? I did a push pull on my AIO with a Noctua F12 3000 if you want to try that as well. It's long power cable should reach your fan controller with no issues.

IJB42 · Answer

I'm still experimenting with the side fans as there are 4 possible combinations of push and pull. Currently, I'm running both fans as exhaust rather than intake but I have yet to try running the fan closest to the back as intake and the other fan as exhaust.

In any case, running both fans as exhaust did seem to delay the GPU from hitting max temperature for a while and did lower the max temperature of the "hot spot" to under 87*C when it previously hit 88*C consistently. Of course all this is a bit odd as the monitoring program also says that the GPU fans are only running at 66% even at the highest GPU temperatures, so it seems like the fan curves on the GPU may be a bit weak. Of course, even at 66%, the fans are quite loud. Thus, so long as I don't see any throttling and the temps don't exceed 90*C, I think all is OK.

As for the CPU, I just ran Intel XTU's 5 minute stress test which runs all cores at 100% for 5 minutes. I have XTU running a very mild overclock as well. The max CPU temperature was 86*C and only for very brief spikes, with the average during the test around 78*C. I don't recall the results when stock, but this shows lots of thermal headroom for the CPU since it does not throttle until 100*C.

Based on this, at least for an i7-12700k and light overclocking, I think the stock liquid cooling is more than sufficient.

Lime21 · Answer

Thanks IJB. It's good to know cooling is good enough for your combo of powerful CPU and GPU.

For the side 92 fans, did you have to remove the GPU bracket? I'm having trouble getting a 2nd one in there. Could you share a picture when you have a chance? Thanks in advance.

IJB42 · Answer

I did not need to remove the GPU bracket or make any changes to existing components with one exception. I had to bend the wires attached to the power plugs that plug into the top of the GPU as they were sticking out just enough to touch the side fan blades. With a bit of gentle pressure, the wires now sit more flush with the plugs and do not touch the fan.

I'm away from home at the moment so cannot post a photo. For the 92mm fans, I installed them at the far ends of the side vents. The rear fan is mounted to the holes closest to the back of the case and the front fan is mounted to the holes closest to the front of the case. I used the rubber mounting pins supplied with the fans. I only used 2 pins per fan, one at the top corner and the other at the diagonally opposite bottom corner. That seems sufficient and makes it easier to remove the fans than if all 4 mounting pins were installed.

Lime21 · Answer

Thanks for clarifying. Have a save trip.

My bracket is installed on the right most slot so it prevents the right fan. I've tried moving it since the actual GPU contact point is small enough not to hit the fan but it doesn't want to go into either of the 2 slots on the left.

Given that the opening is 240mm long 80x3 would be good too without the bracket, or even 120x2 with a bracket (if you have the air cooler)

Lime21 · Answer

In terms of GPU temps the side fan (I used an arctic F9) as intake blowing on the VRM side made the most difference for me - 2-3 degrees C cooler during gaming, which meant less GPU fan noise and stress. Adding a 2nd side fan didn't help much more than that for me.

I also tried putting it in 2 other locations

- On top of the passthrough GPU fan side as pull - didn't make much difference - maybe with a stronger SP fan it would.

- Behind the GPU (outside the case) as exhaust - I wanted to pull the hot GPU air outside the case before it got to the CPU - no measurable impact too.

Furgus · Answer

@Lime21​ I was wondering about the side vent, I might have that up my sleeve...  I literally just de shrouded my RTX 8090 and did the 120mmx15 x2 cabletie hack.  I just did some game tests (150 fps) and the temp is mid 70s, never once over 80.  The BEST benefit though is I now don't have a small aircraft under my desk anymore!!  The fans running at under 1000RPM,  the difference is amazing, I haven't even used the noise reduction cable yet.  The noisiest part of my setup is now PSU fan (Noctua NF-A6x25 ordered) and the liquid cooling pump (will be moving to premium fan option).   I know its a bit hacky, but it really does seem to work fine (I have trimmed the cable ties BTW:)):

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XPS 8950, three Noctua fans cooling experience

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