For the record, there's another source for "keyboard lagging" in DOSBox: the "priority" setting in dosbox.conf. On my ageing gaming system (P4/2.6Ghz/1GB), the default setting of "higher, normal" produces heavy keyboard lagging. I see this effect with other programs on this system, too, when setting the priority of a proccess to anything above "normal". The machine has a rather crappy SiS chipset, maybe that's why it behaves that way.

Didn't play around with typematic yet, and had no reason to do so, too. Didn't notice any "slow movement" effects so far, not even with BAK (as far as i remember).

It simply happens with crappy pcs (my old laptop, too) when the input thread
doesn't catch up fast enough.

The issue is not "lag" of the keyboard input in this case, it's the delay between when you press a key and when it starts auto-repeating. I noticed BAK has some preference settings for small/med/large step and turn sizes, and this feature of discrete steps leads me to believe that the game looks for complete keystrokes by design, hence the relevance of typematic.

Turbokey also works beautifully with Pool of Radiance v1.0
Pool of Radiance v1.0: Tandy Music + Sound effects + SuperSpeed!
Significantly speeds up keyboard response.
priority=higher,normal