Malik wrote:

Are there any differences, in terms of performance, between an actual memory board with it's driver, and the expanded memory emulators like emm386 or qemm?

Search InfoWorld:
Expanded Memory in Transition - On page 56 is a box about EMS simulators and emulators.
EMS 4.0 Boards - EMS in 1988.
more... - post any useful EMS board comparisons here, if you find any.

It will depend on the board. In a 386 you would need a fast EMS board, on a 486 an emulator would probably be faster emulating EMS with XMS.

Malik wrote:

Can the ISA memory board be used on a 386 or a 486?

Yes

Malik wrote:

Can the on-board expanded memory co-exist with emm386?

Never tested it, but I guess you have to be able to turn the EMS board on/off to use emm386 - they probably will use similar/same addresses for the memory window.

Malik wrote:

If it can be used in a 386 or 486, will using the board - by loading it's driver put these systems back on real mode? Or is it possible to run the system with expanded memory in protected mode? (If that's ever possible.)

(Guessing) Drivers/extenders etc. have to be compatible (VCPI/DPMI).

Thanks for the links. So these boards are more useful on a 80286 class. I just wondered if it's possible to put a 486 in a protected mode with the presence of ems.

Yes, this is possible with alternative drivers, e.g. EMM286. If you want UMBs as well, there are hardware UMB drivers for most chipsets.

UMBPCI is the best among them, but it doesn't work on 486 machines, even if they have PCI. However, if you look at the bottom of the UMBPCI page, there are some alternatives listed.

Great! Yes, I've been using UMBPCI in my P3 system. I think the HIRAM and RDOSUMB might be useful for my 486. Can anyone please translate the README files for the HIRAM? They're in German, I think. Thanks!

Why do you want to use an EMS memory board on a 386/486? I do not see any particular advantage, unless your motherboard supports a very low amount of motherboard memory or uses some proprietary memory modules.

Disadvantages of separate EMS boards on a 386/486:

Much slower than using on-board memory due to the ISA bus. ISA bus memory runs at a maximum of 8.33MHz; 386/486 memory runs from 16-33MHz (40MHz for some non-Intel CPUs)

Needs an ISA slot, typically full length

Inconvenient to disable if program will not work with EMS memory

Great Hierophant wrote:

Inconvenient to disable if program will not work with EMS memory

Will the presence of this expansion board alone inhibit such a program from working, even when the board's device driver is not loaded?

Don't know of anything that would directly interface with an ems card,
so disabling the driver (or the int67 interface) should be enough.