Should the pagefile be placed on SSDs?
Yes. Most pagefile operations are small random reads or larger sequential writes, both of which are types of operations that SSDs handle well.
In looking at telemetry data from thousands of traces and focusing on pagefile reads and writes, we find that
- Pagefile.sys reads outnumber pagefile.sys writes by about 40 to 1,
- Pagefile.sys read sizes are typically quite small, with 67% less than or equal to 4 KB, and 88% less than 16 KB.
- Pagefile.sys writes are relatively large, with 62% greater than or equal to 128 KB and 45% being exactly 1 MB in size.
In fact, given typical pagefile reference patterns and the favorable performance characteristics SSDs have on those patterns, there are few files better than the pagefile to place on an SSD.
Mind, I've actually had experience with OS on a tiny SSD (40GB) and pagefile on HDD. The performance decrease when you've run out of RAM and have to hit the pagefile is not negligible at all. The performance hit was particularly noticeable when I've had Firefox minimized for a while and then try to restore it. It felt like I was back to using an HDD with how long it took to reopen the window.
If you've got plenty of RAM, then I recommend a fixed 256MB-1GB pagefile on the SSD. Don't let Windows manage the paging file size since by default, the pagefile it creates is usually too big (around 1-1.5x of RAM, iirc).