I was just thinking 4.77MHz because a lot of the games on the IBM PC/XT time weren't controlled by anything besides CPU speed so they ran at light speed once MHz started to increase. I thought turning turbo off tried to re-emulate that speed to make those programs work correctly again. I might just be confusing that with an old DOS utility that use to do the same thing.
Thing similar. I had to use it for a game that was running to fast, but I can't remember what it was.
So some systems just slowed the CPU down by disabling caches or skipping cycles. Others really did try to hit 4.77 mHz. I wonder if Delivery Rush can be played on an XT if the graphics were simp... more