Kentie has a really nice patch for Unreal & Unreal Tournament 99 (Along with Deus Ex and Rune) that upgrades the renderer. I highly recommend it!

http://kentie.net/article/d3d10drv/

Nice! Thank you very mutch. :) Was looking for something like this.

Nice, thank you!

This fixed my UT99 on Windows 10 64-bit. Thanks!

Thank you very much! :D

Gracias.

That patch helped with the speed issues (too fast) when running UT99/UTGOTY and Unreal Gold on Linux Mint 17.3, via Wine. Beautiful.

Load these textures with the 2.27 Unreal Gold patch for the ultimate in graphics for Unreal Gold

http://www.unrealtexture.com/Unreal/Website/Downloads/Textures/ExtremeEnd/StockUnreal/UnrealExtremeEnd.htm

The textures are a visual treat for the games.

Guys just use openGL it is superior to the direct 3d /direct x stuff especially during the golden age of gaming...

As stated above grab the 227i patch that matches the version your using from link below.

http://www.oldunreal.com/oldunrealpatches.html

But first download and install the Oldunreal-Multimedia-Patche (OMP) OMP-UGOLD-V0.2.exe from below:

http://www.unrealtexture.com/Unreal/Website/Downloads/Patches/OMP/OMPPatches.htm

or

http://www.oldunreal.com/specialpatches.html

And then just setup to use OpenGL. Also give the high end extreme end texture upgrades a go.

Haven't played in a while and now I get massive stuttering with D3D10... maybe because I updated my drivers (currently running Radeon 16.11.2)? Anyway, "normal" D3D mode still works and I don't really notice a visual difference. OpenGL gives me lighting errors and speeds up the game way too fast, though.

edit: Ok, the graphics are fine with this OpenGL renderer, but it's still too fast.

You can use High Resolution Textures with the Direct3D 10 renderer as it supports S3TC textures natively. Simply copy the .utx files to the Textures folder. No need to install the incompatible patch 227i.

This is a non sequitur because most GOG users will not be using hardware from this same golden age. Users with modern GPUs are definitely best served by the Direct3D 10 renderer being discussed here.

For those with older, less-capable, GPUs, Chris Dohnal maintains OpenGL and Direct3D 9 renderers that are superior to those included with UT99. See this post for more information.

I've never encountered this problem, but you could try forcing the game engine to generate frames at a specific rate. For example:

[OpenGLDrv.OpenGLRenderDevice]
FrameRateLimit=60
SwapInterval=1

Setting SwapInterval=1 enables vsync. Make sure that your monitor is operating at 60Hz also; some Intel drivers sneakily drop the refresh rate to 50Hz when off AC power. If any of this helps, but you find that the input lag is unacceptable, try FrameRateLimit=59. This will introduce a very slight stutter, which is extremely hard to observe in a fast-paced twitch FPS. It will, however, reduce input lag noticeably where vsync is in effect.

EDIT: If, after all this, you are still having problems then you could try the 3dfx Glide driver instead. GOG bundles nGlide with Unreal Tournament, which is a mature and stable Glide emulator. I imagine they did this in order to ensure the best possible compatibility but, for some reason, they didn't configure Unreal Tournament to load the Glide driver by default. As with some of the third-party renderers, one has to click "Show all devices" in the 3D video device selection dialog in order to see it. One can also tune nGlide's settings by running nglide_config.exe from the game's System folder. Compared to the kentie and cwdohnal renderers, expect it to be slower but stable, and missing widescreen support.

Thanks, I got it to work some time after my post and now it runs flawlessly. I don't remember what exactly solved the problem for me but I have played through the entire game without any further issues since.