I turned my attention to my IIsi over the weekend (still can’t figure out the voodoo to bring back my 2400c ) and played with the Applied Engineering QuickSilver card I recently acquired with manual and floppy!
The 32k static RAM Cache is the most interesting thing about it as I have other adapters that add an FPU. I decided to run some benchmarks via Norton Utilities System Info 3.2.1 (System 7.0.1) with the original clock chip and overclocked to 25Mhz with 50Mhz clock chip, with and without the card/cache and FPU:
A neat progression in performance improvement (essentially doubling over stock). The best performance run “Macintosh IIsi/25 + FPU/Cache/D” came when I remembered the Memory Control Panel Disk Cache trick of setting it to 1024k to use up the slower soldered on motherboard 1MB of RAM with disk cache forcing the video memory, OS and all other apps to use the faster RAM in the SIMM slots. If you have the memory a pretty significant improvement on its own!
CPU comparison with the other system in this version of Norton Utilities System Info:
I sold the 8200 to @Paulie who is going to try replacing the PSU to get it working again.
The 475 still doesn't work, it needs further board-level diagnosis to seek out what's going on, it's beyond a PRAM-related issue in my opinion and currently a little beyond my skill level at this point but something worth investigating in the future as I would like a working 475 again.
The 630 is alive and well and I managed to re-attach the front bezel, I would like to do a CF conversion with it but will need to find an adapter that works with its early/crippled implementation of IDE.