G751jy Temperature almost the same after changing thermal paste

[Cannon_19]

I haven't changed the thermal paste in my rog g751jy in 2 years so I did it yesterday. I also cleaned all the dust. Before doing it, while playing Battlefield 1 my gpu was constantly at 86-87 degrees celsius and throttling, while cpu was around 92-97, with clock speeds bouncing between 3GHz and 3.3GHz, also reaching 3.4GHz sometimes. Fan speeds were around 3000rpm for gpu and 3300rpm for the cpu. After I was done with the paste and cleaning, I ran Battlefield 1 again and gpu never went above 75-76 degrees and was always at full speed. CPU however, runs at 3.4GHz all the time, and then it gets to 92 degrees and drops to 2.5GHz and ~83 degrees, and then goes back to 3.4GHz until it's at 92 degrees and it's a never ending cycle. Fan speeds were 3000rpm for the gpu and 3000rpm for the cpu (300rpm less than before for cpu). Idle temperatures are 40 degrees for the gpu and 45 degrees for cpu. Is this a normal result? I'm happy with the gpu results, but underwhelmed with cpu results. It never fell to 2.5GHz before, and why are the fans running 300rpm slower? Did I do something wrong? Any way to fix this? The thermal paste I used was Thermal Grizzly Kryonaut and Arctic thermal pads for the vram and vrm (0.5mm and 1mm). I spread the paste with included spatula, as recommended by thermal grizzly. Is there maybe a curing time for the paste or something?

Here are the pictures:
Before cleaning:



GPU:



After cleaning (I cleaned the vram and vrms too but didn't take a picture):

CPU:



GPU:



New paste and thermal pads:

Thermal pads on the heatsink:



GPU:



CPU:

[Cannon_19]

andreacos92 wrote:
Well, you should let your fans revving so high only if needed, so with temps at 80+ °C. With a good repasting, I assume your system will be quite cool and those speeds will be an extra, and not the usual speed.

Anyway, I use NBFC since years reaching that speeds in heavy gaming and fans are still good without signs of wear or strange noise :rolleyes:

I disassembled it again, here are the pictures:










The ones circled in red had good contact, while those circled in yellow left almost no imprint:




So what was causing the cpu problems? CPU contact looks like it was fine, i might be wrong though.

[andreacos92]

Well, that hard to say just looking at the photo. I reported my experience of when I used pads and I had CPU temps issue (mostly on one specific core), and I suggested you to try with thermal paste only.
I know that is a tedious and expensive process, but I think only thing you can do now is to re-assemble it with thermal paste, at least on the little MOSFETs (ones cirled in red, that have a good contact).

Even in my case CPU contact looked good at the view, but I solved my problem in that way.

[Cannon_19]

andreacos92 wrote:
Well, that hard to say just looking at the photo. I reported my experience of when I used pads and I had CPU temps issue (mostly on one specific core), and I suggested you to try with thermal paste only.
I know that is a tedious and expensive process, but I think only thing you can do now is to re-assemble it with thermal paste, at least on the little MOSFETs (ones cirled in red, that have a good contact).

Even in my case CPU contact looked good at the view, but I solved my problem in that way.

I did some tests with the pads now and I think you're 100% right. Unfortunately, I ran out of paste , so I have to wait for a new one before trying it out.. Thank you though, should've listened to you from the start.
Guess I wanted to use the pads for something since I paid for them already.

[andreacos92]

Cannon.19 wrote:
I did some tests with the pads now and I think you're 100% right. Unfortunately, I ran out of paste , so I have to wait for a new one before trying it out.. Thank you though, should've listened to you from the start.
Guess I wanted to use the pads for something since I paid for them already.

On the one hand, I know this is a bit tedious and it's not great to be stuck waiting for a new thermal paste, I have been through this.
On the other hand, I'm happy that you're on the way to solve your problem 🙂 (and happy because I didn't let you disassemble it again for nothing :p)
Let us know how it ends up.

About the pads, mine are currently gathering dust.

[AtGrigorov]

In the pictures, it looks like you applied the paste perfectly. Anyway, Asus are using only thermal paste on their last products and are considering transition to Liquid Metal.

[Cannon_19]

New paste arrived today and I used it on everything this time, no thermal pads left. Temperature is still the same unfortunately, ~76 for gpu and ~92 for cpu (still throttling from 3.4 to 2.5 GHz like before). I ran out of ideas at this point honestly. Doesn't make any sense to throttle worse than before, when it had 2 year old low quality paste and ton of dust.





Also I successfully added 1TB 860 evo without having to remove anything, I was surprised how small it was:

[andreacos92]

Cannon.19 wrote:
New paste arrived today and I used it on everything this time, no thermal pads left. Temperature is still the same unfortunately, ~76 for gpu and ~92 for cpu (still throttling from 3.4 to 2.5 GHz like before). I ran out of ideas at this point honestly. Doesn't make any sense to throttle worse than before, when it had 2 year old low quality paste and ton of dust.

Mmm, this is strange.

From your pictures, thermal paste seems applied really well. I'm assuming that heatsink is well mounted and screws are tightened properly, and vents are clean.
Anyway, what's your max temps exactly when throttling? In which test/scenario?
And your CPU is throttling straight from 3.4 GHz to 2.5 GHz? If yes, this should not be CPU core/package temp throttling, but CPU VR temp throttling.
What about fan speeds?

Cannon.19 wrote:

Also I successfully added 1TB 860 evo without having to remove anything, I was surprised how small it was:

That looks very nice and clean! Great 

[pndiode]

The closet thermal paste I found for the chips installed on a factory laptop thermal paste was K5 Pro thermal paste. The density of thermal paste for CPU and GPU is to thin for chips.

When you installed thermal pads, it also increased the heat sink distance between the GPU and CPU. Did you use copper shims on CPU and GPU to compensate for that distance?

On laptops, because the clearance between the heat sink for the GPU and CPU is so tight K5 Pro thermal paste with its putty like density will fill in the gap for the chips. Twenty grams of K5 Pro thermal paste is more than enough for one laptop.

Use a syringe to apply the K5 Pro thermal paste (elevates a mess, not required) to heat sink for chips. Mix the K5 Pro for better density before applying or putting in syringe (not required). Just like salad dressing or paint, thermal paste separates somewhat (I could be wrong).

[Cannon_19]

I made a short video with temps and other stuff on screen to give you a better idea of what's happening:

This was in campaign (offline) mode, but when I play online the cpu usage goes to ~90% as well, and throttle happens more often I think.
I can make another video in online mode as well if necessary, just let me know.
I'll post a similar video from before I cleaned the dust and changed the paste, waiting for it to upload.

And here's some stats from HWinfo:

[Cannon_19]

Here's the video from before (before cleaning and repasting):