Slow frame rates running HomeWorld with G400 DH max

[S2K]

I'm losing it !! Would somebody please help me to get rid of the poor frame rates in the intro movie of Homeworld. My cursor freezes up or skips when the menu pops up. It then goes back to normal after 5s. The game locks up after awhile in both D3D and OpenGL modes.

Here's the specs of my computer:

AMD K62 500
ASUS P5A 1.7 BIOS
ALI AGP Driver 1.60a /with AGPutil
ALI IDE BusMaster 3.56
Matrox G400 Max 1.04 BIOS / 5.52 driver /with tweakutil
128M SDRAM 133MHz
Creative 52X CDRom
SB Live Value
IBM 20G GXP HD

In System BIOS:
Graphics Aperture --> 256M
Frame Buffer Posted Write --> Disable
PCI/VGA Palette Snoop --> Disable
Video ROM BIOS Shadow --> Enable
all xxxxx-xxxxx Shadow --> Disable

Desktop --> Windows98SE @ 16bit 1024x768
DMAs are switched on for HD and CDRom
Video Card's in IRQ 11
There are no conflicts between components
Everything freshly installed

I have use the "tweakutil" to have AGP running at 1X and still no improvements. I have also tried setting the read-ahead to none and disable the write cache functions trick but no luck.

And the worse part is that the movie plays seamlessly on a 4M Video Card(running it in an IBM PII 450 system) that I don't even know the name of it.

Please give suggestions, thanks in advance!