If the paste is any good, it would sell like crazy on eBAY or Amazon. Why nobody sells it from Japan?
Ah yes, they have this crazy little site for themselves called Rakuten.
They also use Yahoo commerce called Buyee
& some auction site called Jauce.
Enjoy with the ShinEtsu pastes.
In 2022 there was a store in Japan that sold the paste in small packets, but I can't find the link now.
Amazon had the 7921, but it's sold out, only the 7783D is available today.
Shin-Etsu X-23-7921-5 is old
(2015 ?) and still good today not only my test but in other tests here
Why this paste was/is not popular is a mystery to me, even in my country(Brazil) that buys a lot of stuff
from AliExpress this paste is ignored, but seems to be more popular in China.
I think one of the reasons 7921 is not popular is because it's probably the driest/densest paste out there!
Without heat(hair dryer/heat gun/etc) we couldn't apply a thin layer over the CPU or heatsink.
The guys usually prefer easy-to-apply pastes from well-known brands that are easily available in any store.
Anyway, originally it is an industrial paste sold in kilograms to industries, not grams to final users.
So, someone has to buy a kilogram bucket, put it in a small package and resell it in grams to end users.
Seems to be +- the same case with the American Dow Chemical Company
and its DOWSIL™ TC-5888
Not available in Amazon, but you can buy in grams from
Buy DOWSIL TC 5888 5W Thermally Conductive Compound Grey for $14.99 with Free Shipping Worldwide (In Stock)
Interesting that it is thixotropic
like corn starch.
Again, the same case for the Honeywell
with its PTM-7950
It is not silicon based, but some sort of polymer that has longer life span in high temperature like in direct die notebook/GPU,
when the temperature reach +- 45ºC it melts and do its magic. Also not available in Amazon, but you can buy from
Buy Honeywell PTM7950 SP Super Highly Thermally Conductive PCM Paste for $19.99 with Free Shipping Worldwide (In Stock)
(The "pad" is better)
Linus mentioned that the AliExpress version is lower quality, I read somewhere that the AliExpress "pad" is a thinner version.
Not the best performer for a desktop CPU in this test https://www.laitimes.com/en/article/3hvl3_3ykm7.html
But he used the paste and it needs to dry before mounting the heatsink and both the paste/pad
will need proper pressure and some time working at higher temperatures to achieve maximum performance.
The Chinese https://www.halnziye.com/product/277.html
also made a PCM(Phase-change material
) paste with better specification than the Honeywell PTM7950.
If it is really better(performance and life span) I do not know. Found a review, click in the image.
The review is too simple/superficial, but maybe better than nothing...
The main advantage of PCM pastes is their lifespan at high temperatures, they melt but do not break-in/pump-out because they have longer molecular chains.