PC processors entered the Gigahertz era today in the year 2000 with AMD's Athlon
https://www.tomshardware.com/pc-components/cpus/pc-processors-entered-the-gigahertz-era-today-in-the-year-2000-with-amds-athlon-amd-hit-marketing-gold-with-its-1-ghz-athlon-beat-intel-by-a-noseNothing since has packed nearly the impact with the exception of going from spinning disks to SSDs.
They were both "seventh generation" according to their marketing, but you could get an entire GHz+ Athlon XP machine for much less than half the $990 tray price from the article.
I distinctly remember the day work bought a 5 or 6 node cluster for $2000. (A local computer shop gave us a bulk discount and assembled it for them, so sadly, I didn't poke around inside the boxes much.)
We had a Solaris workstation that retailed for $10K in the same office. Its per-core speed was comparable to one Athlon machine, so the cluster ran circles around it for our workload.
Intel was completely missing in action at that point, despite being the market leader. They were about to release the Pentium 4, and didn't put anything decent out from then to the Core 2 Duo. (The Pentium 4 had high clock rates, but low instructions per cycle, so it didn't really matter. Then AMD beat Intel to market with 64 bit support.)
I suspect history is in the process of repeating itself. My $550 AMD box happily runs Qwen 3.5 (32B parameters). An nvidia board that can run that costs > 4x as much.
It was the workstation on which I learned Logic Audio before, you know, Apple bought Emagic. I took that machine, running very low latency Reason to live gigs with my band.
Carting around a full-tower computer (not to mention the large CRT monitor we needed) next to a bunch of tube Fender & Ampeg amps was wild at the time. Finding a good drummer was hard; we turned that challenge into a lot of fun programming rhythm sections we could jam to, and control in real-time, live.
The GHz barrier wasn't special. What was much more important was the fact that AMD was giving Intel a hard time and there was finally hard competition.