[jan-jaap]

Short history of SGI 'big iron' graphics:

• The original Geometry Engine, used in the 68K IRIS and 4D Professional IRIS was mostly used for wireframe geometry.
  
• The GT graphics (Professional IRIS) / GTX (PowerSeries) was the first to reliably do depth in hardware, so it could be used for solids.
  
• The VGX / VGXT (PowerSeries) have improved performance and limited texture capabilities. The total texture size is only a couple of hundred KB, and in VGX especially it's not possible for texture to cross a buffer iirc so it's not very efficient.
  
• Reality Engine was the first that could use texture memory without a speed penalty
  

A 4D/210 had a single R3000 @ 25MHz. It ran at best IRIX 5.3, but more likely IRIX 3.3 or 4.0. And that's a problem with a more modern system. It's still possible to run IRIX 4.05H on most R4000 Indigo2's with Extreme graphics, but IRIX 3.x only ran on the brown IRISes. IRIX 4 doesn't run many IRIX 3 apps because it switched from NeWS to X11 for graphics. IRIX 5 will still run IRIX 4 apps.

So, if you want to revive an old application you'll have to be careful. Also, especially in the days of GTX and VGX, application would often have logic of the type 'if graphics  == VGX : do something fancy ; else if graphics == GTX : do something basic ; else message "sorry, bye".

Otherwise, an R4400 Indigo2 Extreme runs circles around a 4D/210 in every possible way. Much faster CPU. Faster memory (and more of it). Faster disks. etc etc. Less things to break, less heat, less noise.

Still, I love my 4D/440 VGX. There's something about it -- if you can't have fast CPUs you've got to have many -- the low pitch hum of the fans and the fact that it still works even though it's 30+ years old. I've got a 4D/380 VGX as well, and I used to have a 4D/210 GTX.