These are optimised OpenGL drivers, made by Chris Dohnal, for Unreal Tournament. They're much better than the one provided when the game was released, being more stable and having a lot of options.
It's a couple new files that go in the UnrealTournament\System directory. To use it, change video drivers in UT, select show all devices, and then select OpenGL Support.
For more information and future upgrades, keep an eye on:
Changes in version 3.7:
- Fixed a bug with ShareLists enabled and the editor that could cause crashes.
- Editor selection no longer uses OpenGL API selection support. This avoids problems with OpenGL drivers with bugs or missing support in this area.
- A couple 227 editor related updates that were also general renderer code fixes.
- The SmoothMaskedTextures option will use alpha to coverage if AA is enabled with 4 or more samples.
- Removed support for using vertex programs without fragment programs. The UseFragmentProgram setting controls both of these and the UseVertexProgram setting is gone.
- Removed compiled vertex array support and the UseCVA option.
- Removed the UseTNT option.
- No longer using sstream for internal debug functionality.
- A few other mostly minor changes.