The speed difference between my brand new 7200rpm 20TB HDD and a random ass sata SSD is still astounding. Sequentially the HDD is only half as slow. But booting an OS or loading files the HDD is maybe a 10th the speed. Small sequential files is where SSDs shine, especially when it comes to high end NVME drives. That’s why iops are always included in benchmarks.
Windows on an HDD takes like 1-2 minutes to boot. A sata SSD is closer to 30 seconds, and a high end NVME drive is like 10 seconds.
I love booting up servers. 95% of the boot process is spent on the ram check. 4% is spent on the actual bios things, and 1% is actually booting the OS.
Even on my home server (a desktop with 64 gigs of ram) the ram check takes longer than the OS.