Enaiel, I can confirm an on the fly, software adjustable FSB for Socket 7 AMD K6 thanks to your work on VIAFSB. Thank you!
My W156C sits on a no-name MVP4 board that supports AMD K6-2,2+, and 3+. The board boots via jumper at 120Mhz, and I was able to switch between 83mhz and 120mhz in software. 75Mhz worked too, but the machine crashed both times when i launched monster truck madness soon after. Lower clocks like 66 crashed the machine still. I want to try at a later date setting the board to 66 from boot and going up from there with VIAFSB which will be very interesting indeed. I was able to go from 120Mhz to 83Mhz, then run setmul to adjust the ratio. Super cool.
Some nuts and bolts. Included in the zip file attached are few dumps of failures. However something is broken with the dump command because setting FSB to, say 66Mhz, it crashes the machine still. When using the dump command, it doesn't crash and just presents a tidy VIAFSB: Unable to set FSB.. and gracefully exits. That said, the same unable to set FSB is presented with 83Mhz when using -d, however it runs and sets fine without (see OUT83.TXT for STDOUT capture on that one).