I think the period between the late 80's and mid 00's if often overlooked, and possibly overshadowed by some prominent tech "failures". However, we went, quite quickly mind you", from 8 and 16-bit chips that require little to no cooling solutions, to 32 (and later 64) bit behemoths that ran at a clockspeed thousands of times faster than chips before, and orders of magnitude more instructions-per-clock. In some ways, it seems insane that you could buy a commodore 64 with a 6502 clocked at 1mhz, at the same time as you could buy a PC with a 486 DX2 at 50MHz. Just a decade after, Pentium 4's with 3GHz clockrates and cooling requirements that far outstripped solutions available became widely available.
That pre-millenium timeframe was a truly significant period where computers went from slow and limited, to absolute powerhouses. I think it's pretty astonishing that even a Pentium II can be a usable machine in this day and age, as long as you acknowledge it isn't going to be lightning fast.