You're being weird.
So, "13" was not a typo. Just out of idle curiosity, why do you have 13 HTPCs?
I didn't say you didn't use SSDs, I was just guessing that if it took "forever" to upgrade to Win10 (although I suppose "forever" could mean anything) that the PC in question didn't have an SSD. In my office we recently upgraded all of the PCs to Win10 from Win7, and they all have SSDs, and the process took less than two hours, as I remember. Perhaps two hours is forever to you, but I thought differently, which is why I drew the hard drive conclusion.
Most PCs also use SATA for SSDs, which is pretty limiting, performance-wise. You really want PCIe connected SSDs, which are usually limited to high-end, somewhat expensive systems.