Minimum SSD read/write speed for Mac photos with large data

I use some SSDs that advertise 1000 MB/s and test at 800-900 MB/s, and that's fine. I don't think that a MacAir has a port that will support 2000 MB/s, and it's not clear to me if the 2000 MB/s figure is for extended time or just for filling a cache.

If you use iCloud Photos, you need to be careful about plugging and unplugging the drive -- Photos is constantly communicating with the Library, whether you are currently using it or not.

Be sure to format the drive in APFS. ExFAT is a Library killer. See this:

            Move your Photos library to save space on your Mac - Apple Support

And buy a 2nd drive, maybe a different brand, for backup. I've recently had two SSDs, same brand, go totally dead.

therahul wrote:

I have found three variants so far — 800 MB/s, 1000 MB/s or 2000 MB/s. Which one should I go for? Which speed is enough?

In my experience any of the three would be sufficient.

I have a 56,000 photo library (184 GB) on an external SSD that has a read and write speed of ~500Mbs. The library opens in 1 second.

Just be sure to get a quality SSD. I recommend SSDs from OWC (MacSales.com). They are considered the premier 3rd party hardware supplier for Macs by most of the experienced users in these forums.

HOWEVER, after re-reading your post I see you have a MacBook Air. If you want a very good SSD to carry with the MBA consider the 500GB, 1 TB or 2TB OWC Envoy Pro mini 

This way you can always have your library with you. Unless you have a really gigantic library the 1 TB size should suffice.