Can too high W/mK thermal pads also be bad for graphics cards components?

[Filingo]

I know it might be stupid question because if the heat transfer is higher.. it probably means it's better, but maybe there's still a reason that some components in the graphics cards use specific pads?

 

Because I bought the Thermalright Odyssey thermal pad and it has W/mK rating of 12.8. And I noticed that my card actually has 2 types of pads: The clay ones (like the Thermalright Odyssey, so I believe it has higher W/mK), and the rubber ones like the Arctic pads with 6 W/mK. So maybe some specific parts are not designed for too high W/mK pads even though it's better?

 

[CommanderAlex]

Perhaps, the engineers figured out we shouldn't be using high W/mK thermal pads that may cost more money on components that will never reach the maximum heat transfer of said thermal pads??? 

Edited October 30, 2021 by CommanderAlex
Typo

[Falkentyne]

7 hours ago, Filingo said:

I know it might be stupid question because if the heat transfer is higher.. it probably means it's better, but maybe there's still a reason that some components in the graphics cards use specific pads?

 

Because I bought the Thermalright Odyssey thermal pad and it has W/mK rating of 12.8. And I noticed that my card actually has 2 types of pads: The clay ones (like the Thermalright Odyssey, so I believe it has higher W/mK), and the rubber ones like the Arctic pads with 6 W/mK. So maybe some specific parts are not designed for too high W/mK pads even though it's better?

 

 

No.

The "issue" with very high w/mk thermal pads is their compressibility.  The higher pads do not compress very well, making them very unreliable for surfaces that have multiple contact areas, where a pad of the incorrect shore rating or thickness can cause another section to not have proper contact integrity.

 

This causes a problem on any surface where a heatsink piece has to cool multiple areas of different height, because you need a thermal pad thick enough to properly contact the area to be cooled by that section, while also not affecting contact of a completely different section of the heatsink!  The most common scenario for this are GPU heatsinks, where a one piece block with different sections has to cool the GPU core (coldplate) and VRAM and VRM's.  Then you need precise measurements and therefore, OEM's and AIB's prefer to use a very squishy pad, even if the performance is mediocre, since the GPU core will then make good contact with the cold plate and thermal paste.

 

The absolute best high end thermal pad are fujipoly 17 w/mk pads but these are EXTREMELY expensive and unless you're rich, you should probably avoid buying them.  They are also VERY hard and have almost no leeway for compression, and will just crumble apart after first use, if you disassemble the card.  Best to use these on a surface where the heatsink is ONLY cooling that section.

 

Gelid Ultimate 120mm * 120mm pads, or the "2-pack" versions of the 90mm * 50mm pads, are generally a better bargain for high w/mk pads.  They are also a little bit softer than Thermalright Odyssey pads.

 

Gelid Extreme pads are the softest of the higher w/mk pads, making them easy to conform to different surfaces if the thickness needed is a bit thinner than the pad you bought, if contact pressure is high enough (e.g. you actually have enough screws to compress them well).  Unfortunately these can become gummy and melt a bit under high heat, so if you need a pad to tame very high VRM (mosfets) or VRAM temperatures somewhere (e.g. VRAM on a RTX 3090 backplate side), Gelid Ultimates will be better.  But if you need a pad that can cool VRAM on the same side that the GPU core is on, without being so stiff as to not compress, Gelid Extremes are the best for that.

 

Zezzio 14.8 w/mk pads seem to be very recent entry, and they appear to have about the same softness as Gelid Extreme pads.

One user tested them and they seem to perform more like Geild Extremes do, despite Zezzio claiming a 14.8 w/mk thermal transfer.  But as always, the THINNER a thermal pad is, the better its heat transfer will be.  So Zezzio 14.8 w/mk pads may be an option if Gelid Extremes are too expensive.  I do NOT know if the Zezzio pads are more high heat tolerant (e.g. won't turn all gummy) than Gelid Extremes however.  I picked up one of the 2mm 120mm*120mm ones and used a section for the 3090 FE backplate "PCB hotspot" cooling, but for the backplate side VRAM itself, I put on Gelid Ultimate 2mm as I already know how well they perform.

 

https://forums.overclockers.co.uk/posts/35151821/

 

I would avoid their older 12.8 w/mk pads.  Seem to be much harder.

 

Weaker pads tend to be softer and easier to work with and have more leeway on where they can be used.

[Filingo]

13 hours ago, CommanderAlex said:

Perhaps, the engineers figured out we shouldn't be using high W/mK thermal pads that may cost more money on components that will never reach the maximum heat transfer of said thermal pads??? 

Good point

6 hours ago, Falkentyne said:

 

No.

The "issue" with very high w/mk thermal pads is their compressibility.  The higher pads do not compress very well, making them very unreliable for surfaces that have multiple contact areas, where a pad of the incorrect shore rating or thickness can cause another section to not have proper contact integrity.

 

This causes a problem on any surface where a heatsink piece has to cool multiple areas of different height, because you need a thermal pad thick enough to properly contact the area to be cooled by that section, while also not affecting contact of a completely different section of the heatsink!  The most common scenario for this are GPU heatsinks, where a one piece block with different sections has to cool the GPU core (coldplate) and VRAM and VRM's.  Then you need precise measurements and therefore, OEM's and AIB's prefer to use a very squishy pad, even if the performance is mediocre, since the GPU core will then make good contact with the cold plate and thermal paste.

 

The absolute best high end thermal pad are fujipoly 17 w/mk pads but these are EXTREMELY expensive and unless you're rich, you should probably avoid buying them.  They are also VERY hard and have almost no leeway for compression, and will just crumble apart after first use, if you disassemble the card.  Best to use these on a surface where the heatsink is ONLY cooling that section.

 

Gelid Ultimate 120mm * 120mm pads, or the "2-pack" versions of the 90mm * 50mm pads, are generally a better bargain for high w/mk pads.  They are also a little bit softer than Thermalright Odyssey pads.

 

Gelid Extreme pads are the softest of the higher w/mk pads, making them easy to conform to different surfaces if the thickness needed is a bit thinner than the pad you bought, if contact pressure is high enough (e.g. you actually have enough screws to compress them well).  Unfortunately these can become gummy and melt a bit under high heat, so if you need a pad to tame very high VRM (mosfets) or VRAM temperatures somewhere (e.g. VRAM on a RTX 3090 backplate side), Gelid Ultimates will be better.  But if you need a pad that can cool VRAM on the same side that the GPU core is on, without being so stiff as to not compress, Gelid Extremes are the best for that.

 

Zezzio 14.8 w/mk pads seem to be very recent entry, and they appear to have about the same softness as Gelid Extreme pads.

One user tested them and they seem to perform more like Geild Extremes do, despite Zezzio claiming a 14.8 w/mk thermal transfer.  But as always, the THINNER a thermal pad is, the better its heat transfer will be.  So Zezzio 14.8 w/mk pads may be an option if Gelid Extremes are too expensive.  I do NOT know if the Zezzio pads are more high heat tolerant (e.g. won't turn all gummy) than Gelid Extremes however.  I picked up one of the 2mm 120mm*120mm ones and used a section for the 3090 FE backplate "PCB hotspot" cooling, but for the backplate side VRAM itself, I put on Gelid Ultimate 2mm as I already know how well they perform.

 

https://forums.overclockers.co.uk/posts/35151821/

 

I would avoid their older 12.8 w/mk pads.  Seem to be much harder.

 

Weaker pads tend to be softer and easier to work with and have more leeway on where they can be used.

You're so right! I just put 1mm Odyssey thinking it can replace the 0.5mm my card came with, but damn it's so hard that my entire card looks crooked now lol. Need to order new type. Should I order the Odyssey again with correct thickness, or just go for softer ones as well like the Extreme? Or something else completely?

[Falkentyne]

13 minutes ago, Filingo said:

Good point

You're so right! I just put 1mm Odyssey thinking it can replace the 0.5mm my card came with, but damn it's so hard that my entire card looks crooked now lol. Need to order new type. Should I order the Odyssey again with correct thickness, or just go for softer ones as well like the Extreme? Or something else completely?

 

I would go with Gelid Extreme if you are trying to deal with the front side of the card (the side with the GPU core).  You can also try Zezzio (14.8 w/mk not 12.8 w/mk) thermal pads, which are definitely not 14.8 w/mk (they perform more like Gelid Extremes 12 w/mk, but are compressible as well).  For the backplate (assuming your card has VRAM on the backplate side), Gelid Ultimates work very well.

[Filingo]

28 minutes ago, Falkentyne said:

 

I would go with Gelid Extreme if you are trying to deal with the front side of the card (the side with the GPU core).  You can also try Zezzio (14.8 w/mk not 12.8 w/mk) thermal pads, which are definitely not 14.8 w/mk (they perform more like Gelid Extremes 12 w/mk, but are compressible as well).  For the backplate (assuming your card has VRAM on the backplate side), Gelid Ultimates work very well.

Thank you! I do have a backplate, but when I took it apart, I did not see any pads, does it make sense?

And if yes, I will just order Gelid GP-Extreme

 

[Falkentyne]

17 hours ago, Filingo said:

Thank you! I do have a backplate, but when I took it apart, I did not see any pads, does it make sense?

And if yes, I will just order Gelid GP-Extreme

 

Sorry, I meant some video cards have memory on the backplate side of the card (3090 Founder's Edition, RTX A6000, etc)....