Repasting my 775TM GPU with LM - a brief report

My GPU was reaching temps > 90°C in games like the Witcher 3 in a matter of seconds. So I decided to repaste it with Conductonaut. My laptop came with LM on the GPU and delidded CPU, but I hadn't taken of the heatsink, so I was also curious how the reseller applied the LM.

First step: take out the battery and ground yourself.

Those brown squares are little feet to improve airflow. One is missing, I know.

Opening up the case.


Removing the heatsink.

Not a surprise: the LM on the GPU die has completely dried out. Also on the heatsink, where it bonded with the copper.
Big surprise: no delidded CPU, no LM on the cpu, just a thermal pad? I will repaste the IHS/heatsink contact with Kryonaut.

Let's look closer to the GPU die.

I don't know what tape that is, but is that TIM smeared around the borders of the die?

Removing the tape...

Yes it's some kind of TIM. Removing it carefully with a swab and paper cloth. Cleaning the die.

Also the dirty heatsink.


When all the dirt is removed, I tape along the GPU die with TESA tape to prevent damage from accidental LM spillage.


Time to paint the GPU die with a tiny drop of LM, and use a bigger drop to rub in the heatsink.

Then I follow Mr. Fox's suggestion: instead of making foam barriers I make tape 'straws' to stop any LM run off.


Then I paste the CPU IHS with Kryonaut and reattach the heatsink.

Temperatures are now at an absolute low. Running the Witcher 3 doesn't increase temps above 61°C.



The highest temps got with stress testing were 71°C. Without any tweaking I get a 21k Firstrike Graphics score and that's with a conservative undervolt of 1835 at 950V which results in no power or voltage limits. The CPU runs at 4.6 all core, -130 undervolt, at max 75°C, although I haven't been heavily stress testing it.

Of course the real challenge is to see within a few weeks if temps remain stable or start increasing again if the LM dries up / pressure is insufficient - or (hopefully not) if my tape 'dam' doesn't hold.

 

Nice gains!

 

That's a very interesting looking heatsink. I don't think I've seen it before. It's got a different heatpipe arrangement than both the P775DM2/DM3 unified heatsink and the P775TM (Pascal) non-unified heatsinks.

 

I think it's this one.

 

One of the heatpipes is thinner, so maybe it was designed for a lower power GPU like the 1060 or 1070.

 

Nice job, bro. Looks like a decent improvement on the temps.

 

It's actually two different types. The site claims it's for 1060-1070-1080 models.

This is the one I have:


This is the other one:


The main difference is the pipe that bridges the CPU and GPU. In the second type it's a big heat pipe that connects them, while in the first case it's a smaller one. I guess it will depend on the kind of load which type will be more beneficial.

In any case it does the job of removing heat from the GPU well enough.

 

There is that third heatpipe being thicker to the gpu heatsink side too.

 

Yes, so it seems I have the weaker one.

 

Looks that way yes.

 

The P775TM Pascal version is supposed to have the non-unified heatsinks I linked. Not sure why your reseller installed this one instead.

 

Sold as 'heatsink upgrade'

On the other hand, the advantages of a non-unified heatsink depend on the type of workload, as I understand it.

 

It gives a quieter idle and better cooling under individual load.