HP Zbook G6 - hugely improved temps with repaste and uv

[uccollab]

I'm just writing to inform eventual HP Zbook G6 users that repasting and reducing voltage made a huge difference for me.
My setup is the HP Zbook G6 with i9 9880H, Quadro RTX 5000, 64GB RAM and 1TB NVMe.

I was facing really concerning temperatures during intense use. In particular, since beside work I game a little on this device, I was facing a constant 98° under load. I tried a few stress-testing and obtained the same results. This is really bad and while still being theoretically under the maximum operating temp of the chip (which is a bit more than 100°) it will still degrade performance, reduce the lifespan of the chip, and could end up even bending the mobo or compromising other components.

So the first thing I tried is undervolting. For those who don't know, it is the practice to cut the voltage of your components, in order to let them run with less voltage. This doesn't affect the performance (you're not changing the clock, just the voltage) and is 100% safe since the worst that can happen is your PC crash and after a reboot, the stock voltage will be restored.
I needed to downgrade the BIOS (can ben done safely with HP tool) as the latest update removed the ability do UV. I was able to undervolt my i9 with ThrottleStop about 127mV and this improved thermals a bit, but 98° while gaming was still there.
Please note that this is not just a gaming thing, lots of software are CPU and GPU hungry, so you will be facing similar problems.

So I decided to give it a try to repasting. This means changing the thermal paste which acts as a small bridge between CPU and GPU and the dissipation system. I de-assembled my G6 and oh my God, I've never seen a similar mess: https://imgur.com/11mRCtS
Thermal paste is supposed to be put as a small drop (or line in case of rectangular sockets). What I found is a massive amount of paste.

I just can't understand how can HP produce such an expensive and top-performance machine and then drown it in so much thermal paste. If anyone wants the detail, putting so much paste will basically create an insulating plug which will worsen your thermal a lot.

I went on and replaced it with Thermal Grizzly Kryonaut (changed the thermal pads with ARCTIC ones as well) and it feels like a new device. Here are a couple results just for comparison:

Prime 95    ->  before repasting:  95° at the beginning, then settled to 87-90°.
                     ->  after repasting: 90° at the beginning, then settled at 80°

Cinebench -> before repasting:  98° at the beginning, then settled to 90-95°
                     -> after repasting: 90° at the beginning, then settled to 78-80°

But these are just stress-testing results, here's something real-world, with combined CPU-GPU usage:
BFV 1080p, setup max fidelity with Ray-Tracing:
                    -> before repasting: 98° (constant)
                    -> after repasting: 70-80°

Cod Warzone1080p, maxed out:
                    -> before repasting: 98° (constant)
                    -> after repasting: 70-75°

This is insane, I used to blame Intel for his old 14nm architecture but just this quick fix changed it so much and the laptop is more silent and cooler. I definitely recommend anyone who got the tools (or can pay someone to do it) to repaste.