Double post, sorry, I know. This deserves its own post, though.
I didn't know about the D3D9 renderer, so I grabbed that and set it up. I haven't actually PLAYED it yet (I downloaded those new high-rez textures and have a girlfriend to attend to

) but I did set stuff up with what I think are ideal settings. Note that some settings that are in the OpenGL Renderer (Such as CurvedSurfaces) are NOT in the D3D9 one!
(Plus I spent like an hour alphabetizing this list and doing descriptions... so please look at it, okay?
And behold.
[D3D9Drv.D3D9RenderDevice]
BufferClippedActorTris=True
Doesn't really affect much. As Chris Dohnal puts it:
Alters how certain actor polygons are handled, some of which happen to be clipped by higher level code. It's a tradeoff and it is unlikely to make much of a difference either way.
Long story short... probably not worth messing with.
BufferTileQuads=True
Text rendering might improve if this is set to True.
CacheStaticMaps=False
Even the code is vague on this. From the looks of things it's something to do with the node tree, so you probably shouldn't touch it.
ColorizeDetailTextures=False
This makes detail textures colorize as you approach them. Debug Option. Leave False.
Coronas=True
If you like Light Coronas, this is True. If not, this is false.
DescFlags=0
Pointless pretty much. Keep as-is, for me it's 0.
Description=nVidia GeForce 8800 GTS 640
Videocard name. Type it in.
DetailClipping=False
Setting this to True might help on systems with slower, older video hardware at the expense of accuracy on Detail Textures, but anything fairly modern should leave this false.
DetailMax=2
Maximum number of detail textures to render. 2 is plenty; more will just slow things down.
DetailTextures=True
If you want Detail Textures, set this to True.
DynamicTexIdRecycleLevel=100
Leave as-is.
FrameRateLimit=200
Again, keep it to 200 or under. Faster than 200 and your game will run at erratic speeds, especially when you look at walls.
GammaCorrectScreenshots=False
If your screenshots are too dark, set this to True. If they're too bright, set it to False.
GammaOffset=0.000000
If your brightness is maxed out and things are still too dark, try slowly increasing this.
GammaOffsetBlue=0.000000
GammaOffsetGreen=0.000000
GammaOffsetRed=0.000000
All of the above allow for per-channel tweaking of Gamma values. These settings do not get applied, however, to screenshots even if GammaCorrectScreenshots is True.
HighDetailActors=True
Increases the detail in various actors. Most systems can probably keep this True; only extremely ancient systems (Low-End P2s and lower) will take a performance hit from this.
LODBias=0.000000
Positive values will blur textures, negative values will sharpen them. Set this to 0 if you're using S3TC textures.
MaxAnisotropy=16
Maximum level of texture filtering. 0 is none, 1 is Isotropic Filtering, 2, 4, 6, 8, 16, and so on are progressively greater levels of Anisotropic Filtering. Setting this number to something your card can't do will likely give both it and your PC a good heart attack.
MaxLogTextureSize=8
MaxLogVOverU=8
MaxLogUOverV=8
MinLogTextureSize=0
Don't touch these. These control certain sorts of textures and really don't need to be trifled with.
MaxTMUnits=0
This tells the renderer how many texture units it can use on the videocard. It's a debugging option and should be left as 0 for gameplay.
MaskedTextureHack=False
Enabling this option can prevent rendering problems with masked textures when the same texture is applied to different polygons that do not have the masked attribute set consistently across all of them. Likely examples of masked texture problems are rendering errors with solid colored boxes around railings and trees that can often times be fixed with the flush command. There is some risk to using this option, which is why it's called a hack option. It's likely to be very safe, but not completely safe. Implementing it the completely safe way is a lot of extra work, so it uses the simple solution. If it does happen to fail, there will be some completely incorrect textures on some objects.
There you have it. Probably should be False unless you really need it for some reason.
NoAATiles=True
If your HUD is corrupt when you're playing with Antialiasing enabled, set this to true. If you're not using AA, you can keep it false.
NoFiltering=False
When True, textures aren't filtered at all. Keep to false for general gameplay.
NumAASamples=4
Set this to the Level of Antialiasing you want your card to do. Must be a Power of 2. (2, 4, 8 etc.) BIG performance hit on older cards and systems. 4x should be more than good enough for anything modern while keeping speeds plenty zippy. Useless unless UseAA is also True.
OneXBlending=False
Changes the lighting mode. False will make it more like Glide's lighting, which UT was optimized for.
RefreshRate=100
Set to your desired refresh rate. 0 should be autodetect.
RequestHighResolutionZ=False
If you run in 16-bit color, setting this to True will allow you to use a 24-bit Z Buffer in 16-bit color, if your videocard can support it. If you run in 32-bit color, this becomes pointless, as 32-bit color always runs a 24-bit Z Buffer.
SceneNodeHack=True
I have no idea what this does, but from the look of the code, it's pretty ****ing important. Probably shouldn't be touched.
ShinySurfaces=True
Do you like mirrors and shiny floors? Then set this to True. Older systems should gain a performance boost if things slow to a crawl around shiny stuff by making this false.
SinglePassDetail=False
Keep to false unless your videocard is extremely old. Most modern-day videocards will see no real change from setting this to True as they have shader units advanced enough to do stuff in one pass anyway. Older cards might get a performance benefit.
SinglePassFog=True
Unlike SinglePassDetail, this definitely benefits from being set to True. You will likely gain a nice performance increase and the fog will look just as good.
SmoothMaskedTextures=False
I dug in the sourcecode for this one.
if (SmoothMaskedTextures != PL_SmoothMaskedTextures) {
PL_SmoothMaskedTextures = SmoothMaskedTextures;
//Clear masked blending state if set before adjusting smooth masked textures bit
SetBlend(PF_Occlude);
}
//Set smooth masked textures bit
m_smoothMaskedTexturesBit = (SmoothMaskedTextures != 0) ? PF_Masked : 0;
Thus, it appears that all this does is slightly smooth out the edges of masked textures - a poor man's way of AA, perhaps. Probably should be false if you run with any sort of AA, otherwise, try it and see if it works for you.
SwapInterval=-1
VSync. 0 is off, 1 is on, -1 is autodetect.
TexDXT1ToDXT3=False
GeForce 1 through GeForce 4, set True to avoid a nasty bug with S3TC/DXT1 textures. GeForce 5s and up and all ATI cards can keep this set to false.
Use16BitTextures=False
Set this to True for 16-bit textures. These are of lower quality but smaller in terms of how much video RAM they take up. Might be useful for ancient videocards, but anything remotely modern should keep this True for optimum quality.
Use565Textures=False
Set this to False if you're using 32-bit color. If you're using 16-bit color this changes the way textures are done, and may or may not provide a speed boost.
UseAA=True
True if you want Antialiaising, False if you do not. Useless if NumAASamples isn't at least 2.
UseAlphaPalette=True
This mostly affects GeForce 1 through GeForce 4. If false, Masked Textures aren't paletted. Keep this True unless you experience visual anomalies.
UseDetailAlpha=True
Detail Textures will NOT work if this is set to False! Keep it to True if you want them.
UseFragmentProgram=True
Interesting. This seems to do something to Detail Textures, according to the code:
//This function should only be called if at least one polygon will be detail textured
if (UseFragmentProgram) {
DrawDetailTexture_FP(*Surface.DetailTexture);
}
else if (UseVertexProgram) {
DrawDetailTexture_VP(*Surface.DetailTexture);
}
else {
DrawDetailTexture(*Surface.DetailTexture, clipDetailTexture);
}
Basically, it will use the Fragment Program if enabled, or it will use the VertexProgram if not, and if neither are enabled it will simply draw it and then clip the result. I'm basically guessing that it should be set to True for more powerful videocards, but I haven't tested this all that thoroughly yet. More testing would help.
UseMultiTexture=True
Keep this True, as the Renderer needs this set to True to work properly.
UsePalette=True
If your videocard supports Paletted textures, setting this to True will get a nice speed boost.
UsePrecache=True
If set to True, this will preload textures into Video RAM. This will increase load times, but there won't be as much stuttering or hitching. On faster systems this should make virtually no difference.
UsePureDevice=False
Possibly the most enigmatic option yet! MSDN had the following to say.
Specifies that Direct3D does not support Get* calls for anything that can be stored in state blocks. It also tells Direct3D not to provide any emulation services for vertex processing. This means that if the device does not support vertex processing, then the application can use only post-transformed vertices.
Thus, this is probably best left false, as from the sound of things, if you lack the hardware to do a certain operation, it will be done on the CPU in software. This might be worth setting to True if your CPU is absolutely horrid though. Probably useless to set this to True unless UseSoftwareVertexProcessing is also true.
UseS3TC=True
Want High-Rez textures? Turn this on.
UseSoftwareVertexProcessing=False
If your card doesn't support hardware Vertex Processing, set this to True to offload it to the CPU. You'll probably take a frame hit though.
UseSSE=True
The renderer will set this to false if your CPU can't support it, as the code runs a test that only works if your system has SSE. Pentium IIIs and Athlon XPs and up should all support SSE.
UseSSE2=True
The renderer will set this to false if your CPU can't support it, as the code runs a test that only works if your system has SSE2. Pentium 4s and up and AMD 64s and up should all support SSE2.
UseTexIdPool=True
Keep True.
UseTexPool=True
Keep True.
UseTrilinear=True
If set to True, enabled Trilinear Texture Filtering, as opposed to Bilinear. May or may not be useless if Anisotropic Filtering (MaxAnisotropy = 2+) is enabled.
UseTripleBuffering=False
Set this to false unless you're using VSync, as it will actually consume more video memory.
UseVertexProgram=True
See UseFragmentProgram above. Probably the "medium range" option - not quite as good as the Fragment Program, but better than simple clipping.
VolumetricLighting=True
Lights will have falloff if this is True.
ZRangeHack=True
If True, this will fix the clipping redeemer and flashing decals... but it might also make some maps look VERY ugly. (CTF-High, DM-Crane...)