
On my 486DX-50 (really 50, not DX2), my AT bus is set to CLK/3.

At 16.67 MHz, I have no problems.  Soundblaster Pro, Zoom 14.4 FXM, RLL
controller, etc.  All work fine.

If I set it to 2 (25 MHz), I simply don't get past the POST routines.

I doubt you could actually damage much by playing with it.