agent_x007 wrote on 2026-05-18, 19:57:

On Intel chipsets/CPUs : […]
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On Intel chipsets/CPUs :

The attachment Remap option.png is no longer available

For 32-bit OS, always remember to DISABLE memory remap feature in BIOS to get full ~3GB RAM as usable (otherwise, you will be limited to 2GB).
For 64-bit OS, always remember to ENABLE memory remap feature in BIOS to get full 3GB+ RAM as usable (otherwise, you will be limited to ~3GB).

AMD K8 side, has [Memory Hole] options in BIOS (which can be Hardware and/or Software), which work the same way.

I do not think this is correct. I have both Intel and AMD systems where in a dual boot setup (Win XP SP3 32-bit + Win 10 64-bit) I can get the full 8/16GB RAM on Win 10 64-bit and I can get 3/3.5 GB RAM on Win XP 32-bit without changing any settings in BIOS. Both systems have memory remap feature enabled by default but this does not prevent 32-bit XP to reach 2+ GB RAM.

AFAIK the memory remapping option just enables you to use the memory taken by MMIO region behind 4GB otherwise it would remain unused. E.g. the MMIO (PCI, framebuffer, etc.) occopies 0,5GB of 4GB RAM so Windows can see only 3,5GB when remapping disabled. If remapping enabled the unused RAM become available behind 4GB so Windows can see 3,5GB + extra 0,5GB (if PAE enabled). But it has nothing to do about how much ram the MMIO takes below 4GB...

It shouldn't, but it did (at least once for me - not sure now if it was Intel or AMD though, it was on one of the first generations of 64-bit capable platforms), here's similar issue : LINK
I'm not preventing people for trying to use remap all the time, just want to share it can create issues (and how manufacturers recommend you use it).

Note : There never should be any stability problems that come up due to using/not using Memory Remap.
If you have stability issues after enabling this feature, either your RAM settings are unstable (alternatively, memory controller/bus "can't keep up"), OR DIMM/RAM are damaged/broken in some way.

Running 32-bit OS on 4GB+ RAM just does the same thing as "maximum memory/memory limit" option.
It can't make PC unstable or create stability issues by itself.

My problems was caused by some specific drivers that probably was not designed to run with PAE. One of them was e.g. USB Saleae logic analyzer that messed system after data acquision start. But not the only one. Dunno what exaxctly caused the Unreal tournament minilags each 5-10s (only with PAE). So yes, if you're lucky and don't use some specific drivers you may be fully happy with PAE...