Question M.2 pads, when to re-use, replace, etc?

[mikeymikec]

In a PC I built, I had to remove one of two M.2 SSDs and because they were covered by a single 'heatsink', I removed the heatsink which had two M.2 pads on.

I have some spare pads, and the pads on this heatsink are looking a little dusty/hairy as the SSD removal happened some months ago.

As I'm aware that these M.2 pads excrete some kind of (non-conductive) oil, I wanted to know if there's some collective wisdom when to replace them.

 

[mikeymikec]

I had a bunch of M.2 pads spare from things like M.2 enclosures and freebie M.2 heatsinks I've received from suppliers, so I decided to replace the existing pads.

The pads peel straight off the (Asus TUF Gaming) heatsink, and one interesting possibility I considered was to simply flip the pad; the only thing I wasn't sure about was whether the pad would stick that way around as it seemed a bit slippery and I wasn't taking any chances for the application in question. I wiped the surface down with my finger which seemed to do the job perfectly well.

Apparently not all M.2 pads are created with the same thickness so out of two thicknesses I went for the one closest to the pads I removed from the heatsink. When installing the heatsink, there was definite contact going on with the pad and I suspect that when the heatsink is screwed down, it squeezes any thickness of pad a bit already so in hindsight I'd say the thinner ones would probably have worked out too.

I'd say the original pads were slightly over 1mm thick, the ones I replaced them with were probably 1mm, and the thinner ones were... a little thinner

Soon after installation, I was writing about 1TB of data to the drive I connected up today; it wasn't the fastest of transfer speeds ever, but one of the drive sensor temps kept creeping up and peaked at 70C until the transfer was complete, the immediately dropped down to the same temp as the other SSD in the system (covered by a separate heatsink with its original pad). My conclusion is that the pad I installed today is doing its job.