mkarcher wrote on 2025-07-18, 06:13:

Chkcpu wrote on 2025-07-16, 10:06:

If you still want to experiment with this, I can help with writing a “L2WB” Macro for CTCHIPZ. This will take some time though as I need to experiment to find what works, without crashing the system. 😉

The CTCHIPZ version I used some time ago had a bug in its "load memory block" routine, affecting large cache sizes. The standard method to initialize an "always valid" cache is to read a memory block of twice the L2 size (+L1 size, if you don't disable L1 during that time), and CTCHIPZ has a macro-callable function to run REP LODSD (or something like that) for this purpose. In cache the load amount doesn't fit the conventional memory (it doesn't for 1MB or 2MB blocks), it uses a different method that loads extended memory, but there is an arithmetic error: CTCHIPZ will load 1KB or 2KB instead of 1MB or 2MB in that case. Somewhere I likely still have a patched CTCHIPZ around that fixes this bug. I'm gonna hunt for it if you are interested.

Hi mkarcher,

Yes, this CTCHIPZ KB/MB bug would certainly derail the L2 cache WB attempts with 512KB or more cache. I now recall you mentioned this before, so thanks for reminding me about this bug.

Instead of the usual V3.4, I’m using Andreas Stiller’s CTCHIPZ.EXE V3.7 which has the infamous “Runtime error 200” bug on faster CPUs fixed. But I don’t know if this version fixes the KB/MB bug as well, so if you can locate the patched CTCHIPZ version, I would be very interested in a copy.

Thanks, Jan