First post, by Skyscraper
Im starting to really REALLY like this motherboard.
The maximum amount of onboard memory the PC Chips M209 supports is supposed to be 4x1MB SIPP modules as the board can not use its 8 DIPP sockets at the same time to get the 5MB many other 286 boards support.
But wait a minut, what is this?
Click for a large image.
That can never work? or does it?
The PC Chips M209 with the memory installed
The modules I used.
The modules are 3 chip modules which makes it even harder to understand why it works but Im not complaining. These are my only 4MB 30pin modules and they are going to be installed on a couple of SB32 cards but I should soon have some more 4MB modules to play with I hope 😀. I have tested some games and the system seems stable at 20MHz with 16MB and with what I think is 0 wait states both with and without parity activated.
There is one bug though, every other soft reset (like clockwork) the system sees an additional 8MB EMS board that in reality dosnt exist, as EMS is disabled in the BIOS this isnt an issue I can just ignore that message and all 16MB will work. If I enter the BIOS during such a bugged soft reboot the BIOS sees 16MB onboard memory plus a 8MB EMS board and if I save the settings only 8MB memory will be detected the next post as 8MB will be occupied by the non existing EMS board until I enter the BIOS and save settings again during a non bugged reset or a cold boot. I can still use EMS memory if I want to by lowering the amount of XMS memory in the BIOS and and set an EMS memory value that fits under 16MB using the onboard memory. During cold boots everything works as it should every time.
The missing 384KB does not have to do with using alot of memory, this board can simply not remap the upper 384KB of the first 1MB.
New PC: i9 12900K @5GHz all cores @1.2v. MSI PRO Z690-A. 32GB DDR4 3600 CL14. 3070Ti.
Old PC: Dual Xeon X5690@4.6GHz, EVGA SR-2, 48GB DDR3R@2000MHz, Intel X25-M. GTX 980ti.
Older PC: K6-3+ 400@600MHz, PC-Chips M577, 256MB SDRAM, AWE64, Voodoo Banshee.
