@nemail
Some ideas:
Reboot to DOS and run Speedsys (system speed test 4.78), you should get about 120 pts on a Pentium MMX 166MHz
Reboot to DOS and run PC Player benchmark. After running, it shows a list of what certain pentium MMX systems should score.
Just google the above and you will find the software.
Try to test things with the ISA sound card removed. I found a soundcard IRQ conflict can cause a severe slowdown on my socket 7 system.

sisoft sandra is a good thorough benchmark
you can compare your pc against other systems
you will need an older version like sandra 99
http://www.oldversion.com/windows/sisoft-sandra-99

ps: you could try an 80wire ide cable it may help may not