I’m looking to get a new internal hard drive for a specific use case:
- it’s for a desktop, meaning I can fit either
- i need 2TB, no more and no less, also meaning I can get either
- it’s for my media collection, mostly movies
- it’s not gonna be read-only, but I wouldn’t write too often (I would torrent, but all the program’s metadata would be on another drive)
- most likely gonna be formatted with btrfs (subject to change, open to suggestion)
Should I get the 2.5 inch or the 3.5 one?
Thanks in advance.

I think there isn’t much of a difference in your case, but, also, 3.5" are generally a better choice than 2.5" in all aspects except portability.
Higher performing HDDs tend to be 3.5", which might have higher RPM (higher read and write speeds), and bigger solid-state cache to speed up writes. I think 3.5’s tend to be more fault-tolerant too.
In your case, you probably wont need more than the average read speed. A large write cache could be useful, especially if you have a fast internet: if your cache is too small, your download speed will be capped by the write speed of your HDD. Torrenting writes in random access rather than sequential, and random access writes are quite slow on HDDs.
You can circumvent the write cache problem in several ways:
If you are torrenting to the HDD directly, then use a 4K extent size for btrfs or ZFS.
I’ve read that larger cache size can be an indicator of SMR drives. Other than that, I don’t really care about it.
To confirm your uncertainties, I can indeed use the external caching mechanisms on btrfs.
How much would the RPM affect things? I’d think the lower RPM would be less problematic, at least where longetivity and noise is concerned.
Also, what’s your reasoning for the extent size?
Sorry, I realize now that I actually don’t know this much about HDDs. I dont know about SMR, or how rpm affects longevity.
The extent size was suggested by ZFS docs: https://openzfs.github.io/openzfs-docs/Performance and Tuning/Workload Tuning.html#bit-torrent
(I made a mistake. They’re recommended record size is 16k)