Yeah, there were holdouts of course but the DX/2 really seems like the breaking point.
(Also, a Pentium 60 is barely faster than a DX/2 66 at many tasks — it is a Bad Processor — but that’s another conversation ;)
Many tasks perhaps, but running Quake was not one of them.
You could play 320x200 Quake acceptably on a P60. On a DX4 too, though barely - my family had both in the mid 90s. I'd be surprised if Quake is playable on a DX2.
Pentium is a bad processor? It's way faster than 486, especially on FP it's not even close.