I wasn't even sure they were even around but last week I found one on eBay and jumped on it! I've run some tests this evening, and I've made arrangements to have it reverse engineered. If everything goes to plan, there should be some open sourced schematics which should allow anyone who wants one to build their own 
will probably still cost a bit since the SRAM is quite expensive just on its own, but at least it should be available - and maybe someone can find some clever improvements once its documented!
Anyway, some numbers. The test machine(s) are:
- a PM 6100/60 and an overclocked PM 6100/80
- 40MB RAM
- 640 x 480 video, 8 bit color
- System 7.6.1 with Speed Doubler
- HDI-45 internal video (with an extra HPV test)
The tests are:
- Quake 1 FPS using software render at 320x200 running "timedemo demo2" right after launch.
- Marathon 2 FPS (shift+?) fullscreened at 640 x 480 (no HUD). Spawn in - location is random, so strafe to the left corner and backpedal until you stop, wait until framerate stabilizes.
- Bryce 2 render. Time to render a test scene with some geometry and a bunch of different material types
- Finder scroll. Time to scroll from top to bottom of a massive folder, sorted by Name. This is me attempting to quantify the subjective experience of a snappier Finder.
And finally I ran a test with the HPV card - yes, I cracked 12 fps in Quake on a Family Pizza without a G3!
At some point I might get around to making a stripped back Mac OS 8.6 since I've had slightly better performance there but I just hate the long bootup time sooo much
For these very limited tests the bigger cache seems to provide twice the speed boost of the regular 256kB cache - nice! Bryce renders also get a speed increase from the bigger cache but it's dwarfed by the Sick Gainz from having any cache at all.
will probably still cost a bit since the SRAM is quite expensive just on its own, but at least it should be available - and maybe someone can find some clever improvements once its documented!Anyway, some numbers. The test machine(s) are:
- a PM 6100/60 and an overclocked PM 6100/80
- 40MB RAM
- 640 x 480 video, 8 bit color
- System 7.6.1 with Speed Doubler
- HDI-45 internal video (with an extra HPV test)
The tests are:
- Quake 1 FPS using software render at 320x200 running "timedemo demo2" right after launch.
- Marathon 2 FPS (shift+?) fullscreened at 640 x 480 (no HUD). Spawn in - location is random, so strafe to the left corner and backpedal until you stop, wait until framerate stabilizes.
- Bryce 2 render. Time to render a test scene with some geometry and a bunch of different material types
- Finder scroll. Time to scroll from top to bottom of a massive folder, sorted by Name. This is me attempting to quantify the subjective experience of a snappier Finder.
| MHz | L2 Cache | Quake fps | Marathon 2 fps | Bryce 2 render (sec) | Finder scroll (sec) |
| 60 | 0 | 7.6 | 8.0 | 646 | 44.8 |
| 60 | 256kB | 8.4 | 8.4 | 485 | 39.4 |
| 60 | 1MB | 9.2 | 9.4 | 460 | 34.2 |
| 80 | 0 | 9.3 | 9.16 | 569 | 43.3 |
| 80 | 256kB | 10.5 | 9.92 | 394 | 34.9 |
| 80 | 1MB | 11.9 | 11.43 | 360 | 28.8 |
And finally I ran a test with the HPV card - yes, I cracked 12 fps in Quake on a Family Pizza without a G3!
| MHz | L2 Cache | Quake fps | Marathon 2 fps | Bryce 2 render (sec) | Finder scroll (sec) |
| 80 | 1MB | 12.1 | 12.0 | 366 | 29.1 |
At some point I might get around to making a stripped back Mac OS 8.6 since I've had slightly better performance there but I just hate the long bootup time sooo much
For these very limited tests the bigger cache seems to provide twice the speed boost of the regular 256kB cache - nice! Bryce renders also get a speed increase from the bigger cache but it's dwarfed by the Sick Gainz from having any cache at all.
