I've recently come into posession of a used 512GB Sandisk X400, an M2 SATA SSD. I thought I'd try it to reduce the clutter within my case, being able to omit a SATA cable and actually not need any peripheral power cables.

When doing copy tests, I noticed it slowed down from about 250MBps to about 150MBps, which prompted me to run Crystal Disk Info to see what the matter was. It promptly beeped and told me the drive had hit 70*C and I figured it must be throttling. Part of the problem I felt was that I was using an ITX board, with the M2 slot behind. This would severely hinder ventilation and I wondered if the proximity to other warm parts like the CPU and board electronics would have contributed.

Thankfully, the case I have has a generous CPU cutout on the motherboard tray...

Which gave me the idea to swap the doors on the case, since the other door has a 120mm fan mount. I first tried without a fan, to see if the additional ventilation would help but alas, no. So I took an old fan, a USB to 3 pin cable and made a cooling wart on my case.

Previously when gaming, it would go above 60. Now, it stays below 50*C, while still not ideal, I'm a bit more at ease. You can see the SSD label behind the blades, and the 5v input means the fan stays pretty quiet.

I'm wondering how are other peoples experiences with M2 or NGFF drives? Do they run hot, how do you have them mounted? And what types are they (SATA/PCIE)?