Classic DOS Games Forum

Feel free to rate and discuss this utility.

classic but makes games stutter rather than slower.

It sounds like Mo'Slo Deluxe is better at slowing games down in native DOS, and Mo'Slo 4BIZ will slow only one thread so that you can still multi-task in XP or Vista while playing games in Mo'Slo. 4BIZ is hyper threading/multi-core aware, and even lets you assign which CPU core to use (although I'm not sure how important that is). I've never used Deluxe or 4BIZ, but I have a Core 2 Quad, so in theory I should be able to run 4BIZ on one or more cores while still doing everything else at 100%. I often interrupt a game of Blind Wars when I get an email.

I don't think there's a Linux version, but presumably it would work in Wine. You might have to decrease the slowdown effect to compensate for the overhead from Wine.

Okay, this comes straight from the author of Mo'Slo.

"I suspect the writer is either using an older version of Mo'Slo or is unaware that v1.5 has a second, RTC-based slowdown method that does not "stutter" in Windows NT/2K/XP/Vista as method 1 may do at very low speed percentages."

The first programs for the IBM PC and XT expected all computers to have a 4.77 MHz 8088 processor, so they simply can't be played without some kind of slowdown software. Since 4.77 MHz is the slowest that any program is ever going to need to run, and since it's the only speed that software was ever specifically written for, 4.77 MHz is probably the "very low speed percentage" that he was talking about. After the IBM AT came along, programs started to check the CPU speed so that they could adjust to a variety of clock speeds. Method 1 may be primarily designed to overcome the Error 200 divide error that programs compiled with Turbo Pascal run into at around 200 MHz, and method 2 may be better for running software designed for the PC and XT.

According to the Mo'Slo comparison page, Mo'Slo basic has two different DOS slowdown methods. Deluxe has three in real-mode DOS and two in Windows. 4BIZ has two DOS slowdown methods and three Win32 slowdown methods. I've never used Deluxe or 4BIZ, but I may get a chance to test them out in the future. I will definitely test early DOS games if I have the opportunity.