Ya, sometimes you need to play around with the driver order, before HIMEM or after HIMEM. Generally, right before HIMEM is best. I have also seen it where I cannot have DOS=HIGH in config.sys, that is, I must only have written DOS=UMB.

You said that you cannot load DOS HIGH, but then you write DOS=HIGH,UMB. Isn't this loading DOS to high memory first?

JonF wrote on 2024-04-16, 05:28:

Hey, I have PK-X486S50-3 installed in a hot-rodded IBM 5162. I was able to enable the cache and clock doubling via:

Can you tell me how exactly you managed to get the PK-X486S5o working in your 5162?
When I tried mine, I couldn't even reliably complete POST.

I normally use another adapter from Buffalo that uses 486SXL-40. That one works quite well.

feipoa wrote on 2024-05-07, 21:05:

Ya, sometimes you need to play around with the driver order, before HIMEM or after HIMEM. Generally, right before HIMEM is best. I have also seen it where I cannot have DOS=HIGH in config.sys, that is, I must only have written DOS=UMB.

You said that you cannot load DOS HIGH, but then you write DOS=HIGH,UMB. Isn't this loading DOS to high memory first?

I just tried using DOS=UMB and I get the A20 error again when trying to run Jazz Jackrabbit. For some reason, having the HIGH command in there makes the games work even though DOS doesn't load in high memory.

Anonymous Coward wrote on 2024-05-07, 23:28:

Can you tell me how exactly you managed to get the PK-X486S5o working in your 5162?
When I tried mine, I couldn't even reliably complete POST.

I am using a Mr. Bios as an upgrade to the original bios. I have also upgraded the speed of the RAM, both the 2X 256k simms and the 128k chips on the motherboard. Upgraded the speed of a couple of other chips (bus controllers?) Replaced the crystal with 20mhz (10mhz bus). Using an ET4000 graphics card.

See my related thread here:

Generic 80386 bios for Evergreen Superchip 286 -> 486

JonF wrote on 2024-05-08, 19:19:

I just tried using DOS=UMB and I get the A20 error again when trying to run Jazz Jackrabbit. For some reason, having the HIGH command in there makes the games work even though DOS doesn't load in high memory.

Yeah, it can be quite the mixed bag of nuts with these upgrades. Just as you've witnessed, I also have noticed systems that need both the HIGH and UMB to work properly with some apps.

JonF wrote on 2024-05-08, 19:19:

I am using a Mr. Bios as an upgrade to the original bios. I have also upgraded the speed of the RAM, both the 2X 256k simms and the 128k chips on the motherboard. Upgraded the speed of a couple of other chips (bus controllers?) Replaced the crystal with 20mhz (10mhz bus). Using an ET4000 graphics card.

I have pretty much the same setup as you.
When I get back home I'll have to reinvestigate this again.