Are you using SMARTDRV when booting to DOS? Perhaps it could alleviate this stutter.

I manually ran the command smartdrv.exe /x, and then I even put it in my autoexec.bat. However, I am still getting stuttering.

The first thing I'd try would be booting the machine with a clean DOS install (nothing on autoexec.bat or config.sys). Then manually load only the required stuff for the games to run (likely only mouse driver) and see how it behaves. Then start adding stuff (soundcard drivers, PCMCIA drivers, etc) until you get the error. That may help you get the culprit.

I tried running it from safe mode command prompt only so as to have a barebones dos startup. Since I was testing it using Duke 3D, I intialized only the sound drivers. I started up the game and still had the same problem. When I went to reboot normally, it says my HIMEM.sys is missing, yet I looked in C:\windows and located it. Additionally, I tested the games out on a separate but identical machine with no issues. I don't exactly know what is happening now.

So I went ahead and used a boot disk to boot into dos. From there I went to my hard drive and ran doom. I am still getting stutter. Any ideas?

Brute389 wrote on 2021-03-23, 09:23:

Additionally, I tested the games out on a separate but identical machine with no issues.

Completely identical?

It might be useful to swap components one by one and see if you can trace the problem that way. The video card would be a good start, or possibly the memory modules.

I might be inclined to try Fastvid as a software solution otherwise.

Jorpho wrote on 2021-03-24, 05:42:

Completely identical? […]
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Brute389 wrote on 2021-03-23, 09:23:

Additionally, I tested the games out on a separate but identical machine with no issues.

Completely identical?

It might be useful to swap components one by one and see if you can trace the problem that way. The video card would be a good start, or possibly the memory modules.

I might be inclined to try Fastvid as a software solution otherwise.

I mean the only difference is that the other machine was localized for Japan, the C1XF variant, otherwise completely identical. Again, its weird because in windws 98 DOS prompt, Doom runs fine with no stutter. I might just swap the hard drives to make sure it is not a hardware issue with my current machine.

So I went ahead and swapped hard drives, with still the same problems, which leads me to believe it is a hardware issue. Then, I tested it by taking out the memory I had put in it recently, but still the same. This may sound like a dumb question, but could it be an issue with my display cable to the screen? I ask because upon opening up my machine, I noticed 2-3 wires on one end were disconnected. Only thing leading me against that idea, is the fact I have no display problems whatsoever, and again, I can run DOS games fine from the prompt.

Long shot .

Are you using using a USB keyboard on one machine but not on the other ?

EDIT: Another idea--> Are any power management features active in thr BIOS of the problematic machine ?

I do not use a usb keyboard. I went to look in the bios, and to be honest it is super basic with only an auto throttle control or none. I went ahead and reset the bios to default values, making sure no throttle control, and still the same problems. I am starting to wonder if it is somehow the motherboard.

So, this is a laptop without any discrete video card, right?

Brute389 wrote on 2021-03-22, 07:19:

I have a Sony Picturebook C1XS that is experinecing intermittent slow downs in real mode DOS games, yet it is not having the same problem when run in MS-DOS mode from windows 98. For example, I can play Doom fron within windows 98 with no slow downs; however, in real DOS mode, I experience lag every 8 seconds, and it lasts a couple of seconds before speeding right up again.

To be clear: you're running these games by opening an MS-DOS prompt in Windows 98 and then running the games while Windows 98 is still running in the background, right?

If you "Restart in MS-DOS mode", i.e., without rebooting the PC, is the problem still absent?

Fastvid might still be worth a shot. It's possible that there are enough subtle differences between the units that one of them might need it and the other might not, I guess. Maybe you can run CPUID on the two different machines and establish if the processors are of slightly different versions?

Jorpho wrote on 2021-03-24, 14:50:

So, this is a laptop without any discrete video card, right? […]
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So, this is a laptop without any discrete video card, right?

Brute389 wrote on 2021-03-22, 07:19:

I have a Sony Picturebook C1XS that is experinecing intermittent slow downs in real mode DOS games, yet it is not having the same problem when run in MS-DOS mode from windows 98. For example, I can play Doom fron within windows 98 with no slow downs; however, in real DOS mode, I experience lag every 8 seconds, and it lasts a couple of seconds before speeding right up again.

To be clear: you're running these games by opening an MS-DOS prompt in Windows 98 and then running the games while Windows 98 is still running in the background, right?

If you "Restart in MS-DOS mode", i.e., without rebooting the PC, is the problem still absent?

Fastvid might still be worth a shot. It's possible that there are enough subtle differences between the units that one of them might need it and the other might not, I guess. Maybe you can run CPUID on the two different machines and establish if the processors are of slightly different versions?

I apologize for not being clearer; however, I am having problems when I restart in DOS. In windows 98, running DOS games shows no stutter whatsoever, which is what is throwing me for a loop.

Brute389 wrote on 2021-03-24, 16:04:

I am having problems when I restart in DOS. In windows 98, running DOS games shows no stutter whatsoever, which is what is throwing me for a loop.

I am referring to three different things here:
a) Running DOS games while Windows 98 is running.
b) Running DOS games by shutting down Windows 98 with "Restart in MS-DOS mode" (without rebooting).
c) Running DOS games by rebooting and starting in MS-DOS mode.

By c) I mean pressing F8 during startup and selecting "Command Prompt Only", or using a boot disk as you have stated.

I understand you have tried a) and c). Have you tried b) ?

Jorpho wrote on 2021-03-24, 17:35:

I am referring to three different things here: a) Running DOS games while Windows 98 is running. b) Running DOS games by shuttin […]
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Brute389 wrote on 2021-03-24, 16:04:

I am having problems when I restart in DOS. In windows 98, running DOS games shows no stutter whatsoever, which is what is throwing me for a loop.

I am referring to three different things here:
a) Running DOS games while Windows 98 is running.
b) Running DOS games by shutting down Windows 98 with "Restart in MS-DOS mode" (without rebooting).
c) Running DOS games by rebooting and starting in MS-DOS mode.

By c) I mean pressing F8 during startup and selecting "Command Prompt Only", or using a boot disk as you have stated.

I understand you have tried a) and c). Have you tried b) ?

Yes, both options b and c result in stuttering for me. Whereas option a does not.

I see. Well, the CPUID information would be useful if you can get it.

I don't have much experience with it, but my understanding is that Fastvid is specifically intended to compensate for shortcomings in certain revisions of Pentium II processors, and that these problems would otherwise be mitigated by Windows. If the processors in your two devices are subtly different, then that might explain the problem.

(Or at least, no one seems to have better ideas.)

Jorpho wrote on 2021-03-24, 22:25:

I see. Well, the CPUID information would be useful if you can get it.

I don't have much experience with it, but my understanding is that Fastvid is specifically intended to compensate for shortcomings in certain revisions of Pentium II processors, and that these problems would otherwise be mitigated by Windows. If the processors in your two devices are subtly different, then that might explain the problem.

(Or at least, no one seems to have better ideas.)

So I found that the CPUID's of the processors are different. The machine with no issues has a CPUID: SL3EM. My problematic machine has a CPUID: QB59. However, I cannot find any functional difference between them. The line of mobile pentium II's seems to share both CPUID's.

I went ahead and tried fastvid anyways since it was made for pentium II's, and I am still getting the same stuttering.

Well, that's something. That's https://www.cpu-world.com/sspec/SL/SL3EM.html and https://www.cpu-world.com/sspec/QB/QB59.html if anyone else reading this is wondering.

Yeah I am really at a loss right now. I might circle back and do more testing on my functional machine just to make sure this is definitely an isolated issue.

EDIT: I can confirm that my functional machine has no issues with stuttering in either doom or Duke 3d AE.