OpenGL vs. DirectX8.1 - Windows98SE

[Dyre Straits]

I've had ATi cards for a few years now. Along the way I've read a lot about how much better OpenGL looks and runs on certain games.
However, I always seem to have a problem with levels loading VERY slow and gameplay problems and wind up resorting back to D3D.
I did learn that it's best to run an OpenGL game in 16bit rather than trying to set it up with 32bit. I've tried a few other things to get better performance, but, it becomes more frustrating than it is to just play the game in D3D.
One thing I do notice, however, is that fogs often look more real in OpenGL than they do in D3D. That is, whenever there's actually a choice.
Anyone have some tips on getting the best performance with OpenGL? I've tried a few things using Rage3D Tweaker and setting up the Display Properties for Performance. The biggest problem seems to be the unusually long load times when first starting the game and then changing or loading maps within the game. Otherwise, it's pretty good.

Dyre Straits

[systems]

Hi,

which games are giving you trouble? Regarding the fog thing, try setting (or unsetting) fog table emulation / table fog.

ATI cards have always had better driver optimisation towards D3D (remember how long it took them to include OpenGL in the Rage drivers?) However, I'm not getting the problems you're mentioning. I play Serious Sam in OpenGL mode and it runs better than in D3D.

Post back a list of games and I'll wrack my meagre brain with some things for you to try.

[Dyre Straits]

Several Games based on Unreal Engine...

The first ones that come to mind are Unreal Engine-based games:

Deep Space Nine - The Fallen; Rune; Unreal Tournament....etc.

But just about any game that I've selected to try and run it with OpenGL, I get the above trouble.

Some history on DS9-The Fallen:

When I first played the game, I had an AIW 128 32 MB AGP card. I HAD to play it in OpenGL as DirectX7.0 was horrible! Once DirectX8.0 came out, I upgraded and then D3d was tremendously better than OGL. But, with D3D there were terrible artifacts in the game.
When I further upgraded to my RADEON 64 DDR VIVO, the game's playability and graphics improved immensely! However, OpenGL has plagued me consistently with the above trouble.
Rune has the same problem. I had to play it through in D3D...even though the game looks better in OGL....except for initially darker ... but that's corrected with Gamma setting.

Thanks,

Dyre Straits