The BIOS is most likely the limitation. The board would probably run a standard K6 OK but not a K6-2 (K6-2 first came out late May 1998, your cpu is from 2000+/- and the latest BIOS is 08/21/97)

Thanks Horun, you just inspired me to try a regular K6-2. It´s also detected as "80486DX-S @ 66 MHz", but write allocation c a n be turned on with "setk6d" now.
Same goes for a K6-III.

Still not sure what the reason might be.

Maybe the user "Jan Steunebrink" could help you and mod your bios for a better K6-2/III+ support. Here is the thread: DIY Bios Modding guide Jan Steunebrink k6-2+/3+ 128gb

@NostalgicAslinger, Thanks for the heads-up. Yes, I believe I can help with this BIOS.

@majestyk, Looking into this 08/21/97 BIOS is see basic K6support, so patching for K6-2/-III/-2+/-IIII+ support is possible. This includes Write-Allocation support for the CXT core.
Let me know if you like to have this BIOS patched. I will put it on the list then. 😉

Jan

Hello Jan, that would be great!

The latest BIOS I found is this one:

Thanks in advance!

majestyk wrote on 2023-03-17, 16:56:

Hello Jan, that would be great! […]
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Hello Jan, that would be great!

The latest BIOS I found is this one:
5te2.zip

Thanks in advance!

Hi majestyk,

Thanks for the latest SY-5TE BIOS.
The patched version of this BIOS is ready and I send you a copy by PM so you can test it.
When tested, I will put it on my Unofficial K6-2+ / K6-III+ page and up here as well. 😀

Jan

majestyk wrote on 2023-03-25, 13:58:

K6-2+ and K6-III+ CPUs are detected correctly now, but as "375 MHz" while running at 6 x 66 MHz. (Speedsys, cachechk etc. id the […]
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K6-2+ and K6-III+ CPUs are detected correctly now, but as "375 MHz" while running at 6 x 66 MHz. (Speedsys, cachechk etc. id them as 398.40 MHz.)

All 3 caches are working fine according to "cachechkv7".
Write Allocation is enabled according to CTCM 1.7 and the memory write graph in Speedsys.

I was testing with 64MB RAM.

Hi majestyk,

Thanks for testing the SY-5TE patch J.1 BIOS. Great that the CPU detection and Write-Allocation work as expected now. 😀

To fix the 375/400MHz CPU speed issue, I've made a new patch J.2 BIOS version and send you a copy via PM.
Please test this new J.2 BIOS, I expect it will fix the speed display issue.

Cheers, Jan

Thank you, Jan!
I can confirm the new "j2"-version detects K6-2+ and K6-III+CPUs correctly now as 400 MHz (@6x66).

This formerly crippled mainboard can now deal with a variety of advanced socket 7 CPUs (provided a suitable VRM is installed).

majestyk wrote on 2023-05-14, 18:59:

Thank you, Jan!
I can confirm the new "j2"-version detects K6-2+ and K6-III+CPUs correctly now as 400 MHz (@6x66).

This formerly crippled mainboard can now deal with a variety of advanced socket 7 CPUs (provided a suitable VRM is installed).

Great! Thanks for reporting back so quickly. 😊
I'm planning an update of my Unofficial AMD K6-2+ / K6-III+ page tomorrow and will add the SY-5TE patch J.2 BIOS then as well.

Jan