analog_programmer wrote on 2024-12-22, 16:55:

I've never considered an upgrade from Am386SX to a 486SLC CPU on my M369F mobo, but it wouldn't cross my mind to do such a thing in the future either, just to see what happens with the L1 cache control registers depending on the BIOS "Cyrix cache" setting.

I might at some point, one of the PT391A doesn't look so good, if there's too much damage to that one, I might either order a respun M396 board to transplant to, or if the same footprint board I've got somewhere with an Am386sx25 turns up, stick the 486slc on that one, but I am not sure if that's one of these SARC chipset boards or not or an ALI or what until I find it.

BitWrangler wrote on 2024-12-22, 20:31:

I might at some point, one of the PT391A doesn't look so good, if there's too much damage to that one, I might either order a respun M396 board to transplant to, or if the same footprint board I've got somewhere with an Am386sx25 turns up, stick the 486slc on that one, but I am not sure if that's one of these SARC chipset boards or not or an ALI or what until I find it.

Ok, but it has now become crystal clear that the 486SLC CPU will work not reaching its full potential on this particular motherboard because of the missing two cache control signals. Besides, it seems like we still don't have available datasheet for this SARC RC2016A5 chipset, so we don't have any clues on how to modify the chipset connections or add a DIY cache controller PCB.

Yeah but if I have the CPU I am not doing any unicorn hunting on it's behalf, I'm using what is already here, or buying a cheap PCB. Still gonna be faster than a 40Mhz SX, hence an upgrade to the board. Or replication of another known to have BIOS "cope" code. Otherwise, it's over $100 for a confirmed to work 386sx board on fleabay, and there's not many "late" ones that would have a chance of being advanced enough to run an SLC better, and possibly few of those that didn't get an SLC on at the factory. Then you're feeling silly paying that much to get an SLC when you could get a "real" 486. It's like why "waste" a Pentium 150 on a 430FX board? VX/HX/TX are so much better, but still, it's a good CPU for the board, even if it's not a good board for the CPU. Games of bottleneck leapfrog don't end until you're dropping $5000 on the latest and greatest, and then you're only good until the next quarterly announcement. Or you pick somewhere to stop. Anyway, if I'm on my own, welcome to Shitty486ville, population 1, last chance for gas until SLC2town.

BitWrangler, If you have an unused 486SLC CPU, do it. And don't forget to share how the system is behaving after the M396F's upgrade 😉