HD3850 AGP: OpenGL non-functional, unless AGP aperture set to 256mb

I just got the card yesterday, and the first thing I noticed is that my screensaver (programmed in OpenGL) was going about 1 FPS. Just accessing the screensaver tab would crash the Display Properties window. Then I went to play a demo for a new game, Eufloria, which also seems to based in OpenGL (judging from some file names in the program folder). That game would freeze up as well.

So, following a post in a related thread, I increased my AGP aperture size. Suddenly, everything ran smoothly. I guess this means the HD 3850 doesn't allocate any memory to openGL applications.

So my first question is: Is there a way to fix this problem? Can I get the HD 3850 to allocate memory to OpenGL applications?

My second question: Will having a 256mb AGP aperture hurt the performance of non-OpenGL games, because I only have 1.5GB of RAM?

Thanks in advance for the replies. This card is kicking ass in all my other games by the way. Trine looks incredible, and the Half Life Episodes are all nice and shiny.

My system specs:
P4 2.8ghz northwood
1.5gb ram
intel d875pbz mobo
audigy 2 running Kx drivers

EDIT: Forgot to mention I'm using the latest drivers from sapphire's website, hotfix included (I have no idea what the hotfix is).