Yeah, I've got a tip to make Duke 3d run better: Use a native version.
Its source code was released some time ago and some people have made ports for linux and windows.
Here's one port for windows:
http://www.rancidmeat.com/project.php3?id=1

another way is to set the screensize a bit smaller.

Another Duke port is here:
http://jonof.edgenetwork.org/buildport/duke3d/

TSSHP for System Shock (but only pre-alpha):
http://tsshp.sourceforge.net/

I have System Shock working perfectly in DOSBox 0.61 with a frameskip of 2 and the cycles at 10000. I have the System Shock CD version (using cdshock.exe).

There are both VGA and SVGA versions of System Shock. From what I have heard, the floppy version is just VGA, CD version contains both VGA and SVGA. I think VGA version should be well playable in DOSBOX on Athlon Xp 1800+ .
SVGA probably not (SVGA is slow in DOSBOX) - at least this is what I have heard (I have only VGA).

Mirek

I'm playing the SVGA version at 640x480. It is set from the options menu while in the game (video option). It is playing very smooth for me in DOSBox with the adjustments I mentioned. I use an opengl port of Duke3d found at:
http://jonof.edgenetwork.org/buildport/duke3d/

It still doesn't work that well with those changes to frameskip and no. of cycles 😒 I can get SS running through tips from the TTLG forums, but the music is a bit odd, I know this as when I play through DB, the game runs slow but the Music is fine. The speech is fine, its just the MIDI music.

Are you using the cd version of System Shock? Here's my cyb.cfg file:

idi_list 3
lowres_cutscenes 0
midi_io -1
midi_irq -1
inp6d -1
digi_list 2
joystick 131
midi_card 3
midi_dma -1
midi_drq -1
cd_data_dir_path Y:\cdrom\data
digi_io -1
digi_irq -1
digi_card 15
digi_dma -1
language 0
digi_drq -1

Speaking as a frequent poster on the TTLG + FM creator (level creation) for System Shock 2, I`ve heard this question asked many times over at TTLG. If your lucky enough to still be using windows 98 all you need to do is run the "MS-DOS Mode for Games with EMS and XMS support" shortcut, and SS1 should work fine with that. If your using XP your in double trouble though (unless XP has the shortcut also), since even System Shock 2 wont run full stop on XP, and neither will any of the Thief games since they use the same engine. So I`d recommend uninstalling windows XP and putting back on the far more games compatible win98 if your looking to play those games + a mountain of numerous other games which dont work full stop with XP.

SS2 runs fine on my comp, and I have Win XP, all I have done is installed the last official patch (I think its shkpatch.exe) and I set the compatibility mode to Windows 2000, and it works.

Yep, I was able to play and beat SS2 just fine in WinXP. I did have trouble getting the movies to work, but ironed it out eventually.