jakethompson1 wrote on 2022-07-08, 21:30:

AlessandroB wrote on 2022-07-07, 20:05:

I did another test: I came into possession of a DX4 WB, well, with this CPU the computer does not start, exactly as it happens with the DX2 WB. At this point I am thinking of an incompatibility with this memory scheme, in fact the DX4 with which IBM has released this computer and WT (I did not know DX4 WT existed). Strange though because the mainboard is compatible with the POD83 which is WB and the Cyrix 5x86 which seems to me to be WB too. AMD 5x86 on the other hand doesn't work ... maybe for the same reason as DX2 and DX4 ????

You have a POST card? Any POST codes or completely dead?

never seen one. all cpu works except DX2, DX4 WB and AMD 5x86

AlessandroB wrote on 2022-07-08, 23:18:

jakethompson1 wrote on 2022-07-08, 21:30:

AlessandroB wrote on 2022-07-07, 20:05:

I did another test: I came into possession of a DX4 WB, well, with this CPU the computer does not start, exactly as it happens with the DX2 WB. At this point I am thinking of an incompatibility with this memory scheme, in fact the DX4 with which IBM has released this computer and WT (I did not know DX4 WT existed). Strange though because the mainboard is compatible with the POD83 which is WB and the Cyrix 5x86 which seems to me to be WB too. AMD 5x86 on the other hand doesn't work ... maybe for the same reason as DX2 and DX4 ????

You have a POST card? Any POST codes or completely dead?

never seen one. all cpu works except DX2, DX4 WB and AMD 5x86

I have no source for it, but I believe I read somewhere that IBM BIOSes are picky about CPU IDs, and all those CPUs would have a different one than you started with. Have a dump or link to your BIOS?

I have three questions:
Not satisfied with the DX4 100 which is fantastic CPU to have?

What's the reason to go back to DX2 66? Finally, Why not get DX2 66 with WT instead of WB?

FYI WB processors came in very late in 486 era and required much lastest chipset, it is actually not the firmware support to do this properly, your IBM 330 does not support this WB mode.

Pentium OD are crippled to support most boards out there, meant no WB support IIRC.

Cheers,