Vynix wrote on 2023-07-29, 14:53:

I decided to give Peter Moss' utility a try, and so far, I got some... Interesting results.

Please try the rest of the dosbench suite to test the stability of the systems.
All those features should be treated as kind of experimental.

Peter z80.eu wrote on 2023-07-30, 11:29:

I am missing any help/any utility to enable/disable the internal CPU cache of the Cyrix Cx486DX2 (in fact it is a clone named "It's ST 486DX2-80") in a reliable way.

Just use any tool that can enable/disable the internal CPU cache of an Intel 486 processor. The algorithm to enable/disable the L1 cache on the Cx486DX / Cx486DX2 is identical to the algorithm used on any other standard 486 processor. It's toggling bits 30 and 29 of CR0. In case you want to toggle the L1 cache of that Cyrix CPU between WB and WT mode, you might want to use https://github.com/karcherm/cx486wb (full disclosure: I'm the author of that tool). The release ZIP file contains the assembled version of the three utilities.

Peter z80.eu wrote on 2023-07-30, 11:29:

I am missing any help/any utility to enable/disable the internal CPU cache of the Cyrix Cx486DX2 (in fact it is a clone named "It's ST 486DX2-80") in a reliable way.
I've tested several 486DLC tools, but they do not work or do not even start (because it's of course not a 486DLC), the 5x86 utilities are not working for the same reasons.
For sure the Cyrix Cx486DX2 has an internal CPU cache and yes, the documentation of the CPU says it can be enabled or disabled (disabled by default unfortunately), but there is no dedicated utility software for exactly this CPU...

In addition to mkarcher's post, after enabling WB cache, please try DMA access, like writing to a floppy disc. Please use a floppy disc with unimportant data.
Please verify the data written to the floppy disc with cache set back to WT.

gerwin wrote on 2023-07-30, 17:14:

[snip]
Speedsys has a build-in function to export to what you see on the screen to a pcx image, by pressing the R-key when tests are done. You can then convert that saved pcx image to png (or gif) and attach it to the forum.

Oh about that, quite embarrassingly I did export the PCX files, Just that like an idiot I forgot to actually transfer the files from my PM7500 to my PC. I'm working on it atm..

@Disruptor - yes that's planned, I'm just having some issues with transferring files, but normally in a few days, I'll be able to post some results. Although given that it's not really a full PC (it's kind of what a Softmodem is), there might be some unusual things cropping up. (like 5x86.exe causing the whole card to lock up when called using LH in autoexec.bat)

mkarcher wrote on 2023-07-30, 17:44:

Peter z80.eu wrote on 2023-07-30, 11:29:

I am missing any help/any utility to enable/disable the internal CPU cache of the Cyrix Cx486DX2 (in fact it is a clone named "It's ST 486DX2-80") in a reliable way.

Just use any tool that can enable/disable the internal CPU cache of an Intel 486 processor. The algorithm to enable/disable the L1 cache on the Cx486DX / Cx486DX2 is identical to the algorithm used on any other standard 486 processor. It's toggling bits 30 and 29 of CR0. In case you want to toggle the L1 cache of that Cyrix CPU between WB and WT mode, you might want to use https://github.com/karcherm/cx486wb (full disclosure: I'm the author of that tool). The release ZIP file contains the assembled version of the three utilities.

Mea culpa, but I expressed myself not exact enough... yes, I liked to enable the write back cache, not only the CPU cache. In fact, I already found WBOFF (and WBON of course), and yes, it worked fortunately, thanks.
I am still missing the possibility to enable additional CPU settings, e.g. Burst Write Cycle (BWRT). Or I just didn't understand the Cyrix documents (these documents were related to implement settings in the BIOS).

Disruptor wrote on 2023-07-30, 18:05:

Peter z80.eu wrote on 2023-07-30, 11:29:

I am missing any help/any utility to enable/disable the internal CPU cache of the Cyrix Cx486DX2 (in fact it is a clone named "It's ST 486DX2-80") in a reliable way.
I've tested several 486DLC tools, but they do not work or do not even start (because it's of course not a 486DLC), the 5x86 utilities are not working for the same reasons.
For sure the Cyrix Cx486DX2 has an internal CPU cache and yes, the documentation of the CPU says it can be enabled or disabled (disabled by default unfortunately), but there is no dedicated utility software for exactly this CPU...

In addition to mkarcher's post, after enabling WB cache, please try DMA access, like writing to a floppy disc. Please use a floppy disc with unimportant data.
Please verify the data written to the floppy disc with cache set back to WT.

Thanks for the hint, I guess you already made a bad expirience with it. Will test it, too.

So, as promised I ran the DOS benchmark suite on the Apple 7in PC card, and while most of the stuff ran pretty well, there's a few outliers that crashed or locked the whole PC up.

Quake: Out of memory error at startup, attempting to start from a fresh MS-DOS bootdisk yields the same thing.

Landmark: Starts up fine but then got a EMM386 crash. From a bootdisk it runs fine and reports that its running on a 459MHz AT with a 925MHz 287 (LOL)

TOPBENCH: Crash, regardless of using the bootdisk or with or without register enhancements.

DOOM and the other benchmarks ran fine without any weird things, regardless of register enhancements being enabled or not.