How durable is a liquid metal repaste from a reseller?

Putting aside the question of using liquid metal on bare copper for a moment, I am hoping to learn more about how "shock resistant" a liquid metal solution on the CPU+GPU is when done by a tier 1 reseller like HID or GenTechPC?

I've read the massive thread about using foam barriers to ensure that LM doesn't spill onto the board, but I'm not sure how bulletproof a solution is from a place like HID (who won't tell me anything about their methodology, since it's secret). I tend to abuse my laptops a lot, in terms of keeping them in backpacks for long periods of time, and then those backpacks are subject to a lot of shaking/jolting and being thrown around or generally poorly handled (military). Hence I'm quite nervous about ordering a laptop with LM since reading that thread about foam barriers and how easily the LM can escape.

Also, and perhaps a more important question to ask is, does anyone here have any stories about LM from HID/GenTech which failed or leaked? Any bad experiences at all with a reseller applied LM solution?

 

Liquid metal should not leak out past the GPU and CPU area if the correct amount was applied, it tends to "stick" to metal surfaces after you spread it, especially copper. I did not have any issues with it even without using foam barrier. If you are really nervous - just stick to pastes with high viscosity which would resist any pump out or leaking, like IC Diamond or Kingpin kPx.

As for resellers applying it - you never know how well they applied it until you will actually check it yourself ;-) This is why I would never order any repaste option. Of course not everyone is willing to repaste themselves, but I would suggest finding a friend who can do this or reputable local repair shop (keyword is "reputable", someone who will not shift their own fault onto customer).

 

My experience with liquid metal on laptops is that the cost and effort isn't worth it, and the gain is quite small compared to the risks involved.

Even repasting and re-padding isn't worth it on most laptops as well.

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The gain depends on the quality of original thermal paste. On my laptop I have seen 20c difference between liquid metal and stock thermal paste, I can find other similar examples.

 

The gains are tangible only if the paste was the bottle neck. If the rest of the cooling system was subpar the only difference will be quicker temp drops to idle.

 

I'm honestly not too fussed about the gains of liquid metal; I'm much more interested to know how shock/abuse proof LM is when applied by a competent reseller. Even assuming a laptop's LM application has some kind of foam barrier around the die, does that 100% mean you will never leak LM during intense shaking/jolting of the laptop in a backpack?

 

It should not leak if there is no excessive amount applied. Of course, it is hard to do that when you cannot see how much heatsink will squeeze it out, so there is always a chance some inexperienced person will apply too much and some will drop outside of CPU area.

And yes, the barrier should work well against excessive application. I do not know if any reseller uses it.

 

HID uses a custom RTV silicone gasket sandwiched between Kapton tape, while other resellers who offer LM such as Eluktronics use foam.

 

Interesting, many thanks! Apologies for asking this, but how do you know this if their technique is supposed to be secret?

As far as techniques go, I'm so new to all things LM that it's hard for me to understand how good a technique the custom RTV silicone is compared to foam. I do know that silicone is a pretty good sealant, as it's even waterproof (or at least the stuff I use in my shower is), so that seems to indicate that the HID solution is indeed incredibly durable? I mean, if HID are basically creating a ring of silicone around the LM, much like one uses silicone to seal a shower, then that sounds like there is absolutely no way that LM could ever escape, even under extreme jolting and shaking of the laptop as a whole?

 

I have seen recent examples of units purchased from HID with the bottom cover removed.

Yes the RTV method should work quite well.

 

But if you remove the bottom panel of the laptop, say to upgrade RAM or the hard drive, it doesn't in any way destroy or harm the HID custom sealing, does it?

 

No, as long as you don’t take the heatsink off.

 

It's impossible for LM to escape from the CPU package--0% chance of anything being shorted with the HID method.
And I believe it was Mr. Fox who first suggested the RTV +Kapton tape method long ago.

However it is still possible for LM to shift on the die and cause high imbalanced temps after a very heavy jolt, if the heatsink pressure is too low. Keep that in mind. Such a jolt would probably cause other damage to the laptop exterior (or even the HDD if installed) first however. I've seen this happen to some Alienwares after such heavy jolts. If the pressure is high enough, nothing would happen. That's why a proper fit and a flat heatsink with even pressure is important (Doesn't help matters that the CPU die is also slightly convex).

 

That's very helpful, thank you kindly.

Regarding the issue of a flat heatsink and even pressure, I'm guessing this is not something which HID could in any way help with or alter, it is entirely dependent on the laptop's heatsink and manufacturer fit and finish? Is this dependent on a specific laptop model, or even for a specific model, each individual laptop may have different fit and finish to the heatsink as individual tolerances vary wildly?

The laptop I want to buy is an MSI GE75, so I have no idea how flat and high pressure its heatsinks are, such that they would adequately protect against a hard jolt with LM. Do you have any experience with how tight/even MSI heatsinks tend to fit?

Also, one other question, everything which has been said in this thread about LM protection seems to focus on the CPU, but HID also offers LM on the GPU. Assuming they use the same RTV silicone gasket on the GPU as the CPU, is it just as safe to use LM on the GPU as well? Or do most professional LM users don't bother putting LM on the GPU as well?

 

GPU does not heat up as much as CPU, this is why most resellers do not offer to cover it with liquid metal. The only exception is Eluktronics MAG-15 and similar laptops which have 75c GPU thermal throttle limit which is easily reached in games like BF5. MSI GE75 has the usual 87c thermal throttle limit for GPU so using conventional thermal paste should be ok. Of course, if you want the maximum silence from the fans I would put liquid metal on both GPU and CPU.

 

So I asked HID about how they seal the GPU vs CPU, and they mentioned that while it is true that they use silicone on the CPU, they only use foam to seal the GPU.

Silicone seems bulletproof to me, for shaking and jolting the laptop, but am not so sure about foam alone on the GPU. How safe is only foam on the GPU? Perhaps it's better to have LM only on the CPU which is sealed with silicone and use a traditional paste on the GPU?

 

The GPU is different because of all of the tiny SMD resistors all around the GPU core. CPU's don't have those things.
For GPU, all you need to do is just buy some Super 33+ tape, fully tape around (intersecting layers) the SMD resistors, so they are fully insulated, leaving only the core exposed (make sure the tape goes up to the very edge of the core "bottom" and press it down so the top edge of the core is NOT touching the tape), and press all over so there are no gaps in the tape, then apply your cutout foam dam for a protective emergency barrier. The Super 33+ tape stuff works well, and is newbie friendly since it's reversible. If you were ever trying to go back to normal paste (e.g. to RMA or sell), no one would know it was LM'd either (you would still have to sand the heatsink with 2500 grit sandpaper until all of the gallium stain is removed though).

https://www.amazon.com/gp/product/B002GKC2US/

Instead of the Super 33+ tape, you can also use conformal coating on the GPU resistors, but a lot more care is needed (stuff is a bit messy). Then foam dam it after it dries.

https://www.amazon.com/gp/product/B008O9YIV6/

 

Thank you kindly for all of that.

In your professional opinion, how durable and shock-resistant is such a GPU solution, with the Super 33+ tape and foam barrier? Would you say it is as durable against heavy shaking of the laptop as the silicone solution is on the CPU?