[The Fifth Horseman]

You do a few things about that:
1. Open Dosbox.conf and set core to dynamic
2. Change starting cycles to 10000 and the cycleup/cycledown values to 1000.
3. Change output to ddraw or overlay (surface is the slowest one there is)

Now in DOSBox experiment with frameskip and increasing/decreasing cycles until it runs at a satisfactory speed.
CTRL+F7 / F8 increase and decrease frameskip, CTRL+F11 / F12 increase/decrease cycles. I don't recommend setting frameskip too high - 1 or 2 should be more than enough.

Remember to use DOSBox v0.70 for that, BTW, since it's a fair bit faster than the previous versions (and more stable with dynamic core).