H3nrik V! wrote on 2025-04-22, 14:40:It's not super fast on a 486, though 🤣
Well done for hanging on in there and getting it working, wait 'till you try it on a faster i486. On my AMD Am5x86-WT @ 160MHz the save took 4:10 as compared to 13:15 on your 486 SX-WT @ 25MHz.
I wonder if NT4 always has issues on very early i486 such as your 486DX-25 SX308 CPUID 0401 which NT reports as Stepping B0, has anyone managed to get NT stable on this CPU?

Given the system booted and SIV started it must be close to being stable.
I also just noticed https://www.geoffchappell.com/studies/windows … htm?tx=42,61;59 says C0 is reported when there is no FPU and B0 when reading dr4 causes Invalid Opcode exception. I now just need to see A0 for a full set.
The Model + Stepping in the SYSTEM_PROCESSOR_INFORMATION for CPUs without CPUID looks to be different to the Model + Stepping returned by CPUID. Now that I have figured this out I have changed SIV to say Model + Stepping.
I now just need to find out how to tell if the CPU is AMD or Intel, I wonder what happens with UMOV on your SX308 and SX406, to find out do SIV32L -DBGCPU -EXIT=10 > SIV_DBGOUT.log | MORE and look at the .log file once SIV has exited.
Update: From SIV V5.81 Beta-05 you can check Menu->Hardware->CPUID->CPU-0 on both Windows NT and Windows 9x systems.
