Just trying to understand your requirements a bit here Martin. A NAS is a NETWORK attached storage. That is not normally going to be installed inside your PC. The are PCI addon cards that can support multiple M.2 drives. (They may or may not also support NVMe which is an extra option, but as NVMe is basically PCI, and if multiple of them are on one card, they’re not necessarily going to use the full bandwidth, depending on the card.)
If you really do want something with a network connection, and knowing how @Leo (and myself) recommend Synology, I might recommend this to you, but it doesn’t use M.2 for the drives: DS419slim | Synology Inc.
Thank you very much for your text and recommendation. I have looked at the Synology and it looks great. I still need then the matching hard drive 2.5 inch. I have always thought that the hard drives with 5400 RPM are slow.
I just researched and there is actually a 2.5 inch hard drive from WD with 10000 RPM. I think I want to copy more smaller file fragments over the network than very large files. So I think access times and write performance are an important factor.
That’s why my consideration was SSDs! For example, from Samsung. The SATA bus limits, but should be enough for my requirements?
Agree with @big_D, even a single modern 5400rpm disk on a decent NAS should be able to saturate a gigabit network so I don’t think you would see much benefit with SSD/nvme unless your working with a lot of small files where access times are important, so maybe working with a couple if SSDs might give you enough performance without the need for nvme.
Ok great thank you all for your effort and recommendation. Then I will buy 2.5 inch hard drives. I’ll have a look at Western Digital. I have not had any bad experiences with them so far.
One thing to note is that these days 2.5" HDDs are limited in size and (at great expense) you can actually find larger SSDs than you will be able to find HDDs. Synology also makes NAS devices that take larger 3.5" drives but they are larger in size (and you seem set on having a smaller setup.)
Yes, I’d take a3.5" NAS. You have more flexibility and the drives are faster. Plus you can get dedicated NAS hard drives that are designed to run 24/7.