GF4 Ti4600 - Drivers reports only AGP2X :(

My system has a VIA Apollo 133 Chipset with 933mhz CPU and 512MB ram.

I recently bought an Asus Geforce 4 Ti4600 - but I'm not quite sure wether I'm getting all
the performance I should.. Games work quite well, but not as good as I expected.
(example: in soldiers of fortune II, I'm unable to make it go 100% smooth in 1024x768 even though I
cut back on the detail settings)
I tried 3dMark2001 (assuming this product is able to correctly measure
the performance of a GF4-card?), and the results wasn't exactly breathtaking. On the two first
tests (the jeep driving around shootng) I get around 30-40fps on the low detail test, and 5-10fps on the
high detail test. This is comparable with my old Geforce 2MX card..!

I run the latest Nvidia Detonator 40 drivers (v40.72 Beta) and one curious fact from the information
in the nvidia display settings is that under adapter information it claims that I'm running AGP 2X!
I'm positive that my mainboard supports AGP 4x. It even has a setting called "AGP 4x Enabled" in the
bios, (for the record I've tried this setting both on and off, doesn't make a difference )

So what could be wrong? Can't I expect better performance than this with this setup? And why does
my drivers report AGP 2X when it ought to be running 4X?

PS: I've tried the Asus-drivers that came with the card as well, but I didn't detect any noticeable
difference in performance. It almost feels like something is holding the card back, especially when
you consider the results from 3dMark2001.

Hope anyone got any good ideas!

Regards,
Thorbjorn