XPS 15 9550 temperature observations (undervolt + repaste)

I had a couple of hours to mess around with the XPS 15 9550 in my sig (i5 version) and decided to see what temperatures I was hitting. I tested it under Prime95 small fft's for 20 minutes and looked at the average temperature. I tested it first with all stock settings/paste and then undervolted by 185mv (a setting that is prime stable for me). After that I repasted the cpu and gpu with IC Diamond thermal paste, tried it at stock voltage, and then undervolted again.

Here are the results

Stock - 73*C
Undervolt by 185mv - 59*C
Stock voltage with repaste - 68*C
Repaste and undervolt by 185mv - 53*C

One good thing with the undervolt is the fans were also able to run at a step slower - reducing noise output by a fair amount. The undervolt and repaste again allowed the fans to step down again, producing the best results.

Another thing I looked at was my 950pro SSD. My laptop came with the 32gb cache drive, so it did not have the thermal pad. Using AIDA64 I was idling at 40*C and hitting 63*C in ATTO. I put some 2mm thermal pad between the SSD and the bottom case and now it idles at 29*C and hit 39*C in ATTO. A fairly good reduction I'd say.

Figured I'd throw up some results for you guys. I wanted to get some GPU temps (before and after repaste), but I didn't have enough time.

*ON EDIT*
There has been some discussion on trying to cool down the VRM area (~page 50) which seems to be causing throttling for a few members. I have had good experience cooling the R22 chokes seen on page 27 with cheap 1mm thermal pads, however Pressing had a negative one using high thermal conductivity pads on his. YMMV.

Secondvision has put together a great summary with a table of results


So I have had a couple of people ask me to do a repasting how-to so here is a brief one:

1. Get your laptop and tools ready. You will need a phillips screwdriver, T5 driver, something to clean the old thermal paste off (I like arctic clean), new thermal paste (recently tried and absolutely love kryonaut thermal grizzly).


2. Remove the back cover of your XPS 9550.


3. Unplug the battery cable (carefully).


4. Remove the heatsink. See how wonderful of a job dell does at pasting...


5. Remove old paste making sure to clean it well and not get it on anything else.


6. Apply a small line of paste to the cpu and gpu. Note that this application doesn't look very good and it may be difficult to see how much I applied. It's always a good idea to do a trial fit where you apply it and seat the heatsink and then take it off to see how well the application went (you have to clean it and reapply after that though). You can also see that I changed the thermal pad under the heat pipe to one that is around 1.5mm thick because the stock pad did not come near touching the ram chip.


7. Reinstall the heatsink, plug in the battery cable, put the back of the case on...

 

Thanks for this. Would be curious as to how much undervolting extends battery runtime.

What tool did you use to do the actual undervolting?

Also, what was thermal brand/rating of thermal pad?

 

Did the CPU stayed at 2.8 GHz?

Please run Furmark on your machine and post results. Mine stays at around 70C with 1.1GHZ 950MHz core clock. If I run Furmark and primes together I get gpu at 80C @ 1.1GHz, CPU around 70C @2.2GHz.The heatsinks above VRAM are not perfectly flat and cause the GPU plate to make poor contact with GPU. CPU is fine.

Did you remove the sticker from 950Pro? Or did you place the pad on it?

 

I used intel XTU to do the undervolting and temperature monitoring. For the thermal pad, sadly it's just some cheap one with a thermal conductivity of 3.2w/m-K. My good Fujipoly is only .5mm thick... No ideas on how much battery life the undervolting will save, but the fans not running as much will also help a little.

I'll run some Furmark tonight to see what I get. I did not remove the sticker from the 950 pro, I left it on there.

 

Well your temps are certainly better than mine in the GPU. My GPU hits 80*C running just Furmark and then 90*C with prime thrown in the mix. I don't know if I have a bad GPU repaste or what.

 

Can Intel xtu auto undervolt on cold boot? Under volt sounds cool and useful. A must, but it needs to set n forget preferably

 

What about throttling? It should throttle down, the temps I posted were below stock speeds. And what about fan speeds - are they going full throttle? I forgot I had it once on 'quiet' settings and the fans didn;t ramp up causing high temps. I took it apart again, did repaste and some bending of the heatpipe, put some aluminium foil to cover gaps, and right now I when running primes and furmark together I have stable 72C @ 850MHz on GPU and 69C @ 2.2 GHz on CPU.

Have a look at the VRAM modules just next to the gpu fan. Remove the fan to have a better view. I bet that you will see same thing as mine did: a corner of the plate rests on the chip, angled, the other chip has no contact at all with the plate, and the plate is lifted from the GPU.

 

I have XTU autolaunching on startup. I don't know if this is required, but it automatically loads my undervolt profile each time windows starts.

I didn't notice is throttling, but I thought 1.1ghz was stock speed? I will check out the contact between the GPU and the heatsink and see if mine has the same problem.

 

Sorry, it was 70C @ 950MHz, I edited the other post. I'm running it again and after 15 minutes I get 77C @ 1.1GHz with Furmark only.

 

That's pretty good performance I think. Did you change the thermal pad for the VRAMs? If so, what is the thickness of your new pads? Thanks.