[dalf]

I was avoiding EMM386 as much as I could on my slow 386SX25: there was a huge performance hit.

There was the Unreal Mode aka Flat mode. With few lines of assembly code, an memory allocation using HIMEM.SYS, it was possible to access all the memory: the segment limit is 4GB instead of 64KB in this "mode". Of course it was not compatible with Windows, so the unreal mode was more for fun than anything else.

https://en.wikipedia.org/wiki/Unreal_mode