Max Impact was the first workstation I used that delivered solid model rotation at 60Fps. I remember literally feeling that smooth movement and how it made a significant difference in assembly and some interactive surfacing / sketching workflows.

The O2 Copper unified or shared memory design was the first machine I used that could deliver large image and or video manipulation via surfaces. Was amazing to see a huge satellite image and be able to zoom way in, composite other images to sub-pixel accuracy, or model a product featuring high resolution reflections at 60fps.

At the time, PC cards just did not yet offer GB of RAM, but would soon.

The O2 chipset got used in the 320, 540 visual workstations too. The shared memory performed great on some texture memory demanding games, but all the cool features went largely unused. There was going to be Linux X Window support, essentially creating an Intel O2 type computer that could be fast, dual CPU, and big memory capable, but Microsoft cried about it and basically flexed their ownership of the ARC loader SGI used on those distinctive PC's and it all got buried. Not even a leak...

Years later, Apple improved on those concepts with the M1, which feels remarkably like what could have been earlier, ar least graphically.

I agree a Pi4 feels 90's era workstation like. Faster, but not so fast that the feel of that era is gone.