For me, at 52, I recall the SSD transformation to be near miraculous. I never once felt that way about a CPU upgrade until getting an M1. I went from a cyrix 5x86 133 (which was effectively a fast 486) to a pentium II 266 and it just wasn't that impressive.
The drag down of swapping became almost a non-issue with the SSD changeover.
I suppose going from a //e to a IIgs was that kind of leap but that was more about the whole computer than a cpu.
Now I have to say, swapping to an SSD on my windows machines at work was far less impressive than going to SSD with my macs. I sort of wrote that off as all the anivirus crap that was running. It was very disappointing compared to the transformation on mac. On my macs it was like I suddenly heard the hallelujah chorus when I powered on.
I went 386 DX 33 to a Pentium 75, which wasn't a wild amount of time. I'd argue that's way bigger than when I got an SSD (but I agree SSD was a huge improvement).
I went from a 1Mhz Apple //e in 1986 to a Mac LCII in 1992 with a 68030/16 MHz LCII. That was the last time I felt a step change in day to day work. Of course things like games, video and audio encoding got faster.
The next time I felt a step change was the M series of Macs. P
Software was already far down the bloat path by the time the Core 2 Duo came out, so the upgrade didn't make all that much of a difference in feel given how much latency was caused by software performing random reads off a disk. That's why SSDs made such a huge difference.
Back in the MS-DOS days, the amount of data needed to be read off a disk while the OS booted was negligible, so a second or two on a fast 486 felt amazing compared to the incredibly slow grind of watching code execute on an 8086 or slow 80286. Software was still in the space of having to run tolerably on an 8086, so the added resources of a newer faster machine actually did improve the feel of the system.
The drag down of swapping became almost a non-issue with the SSD changeover.
I suppose going from a //e to a IIgs was that kind of leap but that was more about the whole computer than a cpu.
Now I have to say, swapping to an SSD on my windows machines at work was far less impressive than going to SSD with my macs. I sort of wrote that off as all the anivirus crap that was running. It was very disappointing compared to the transformation on mac. On my macs it was like I suddenly heard the hallelujah chorus when I powered on.