9600 Pro Benchmark Question

I've just installed my big Christmas present, a "PowerColor" 9600 Pro card.
So far I'm very impressed by it. My old card was a 32Mb GForce 2 MX...

The rest of my system consists of the following: ECS P4VXASD2+ Mobo (Via
Apollo P4X266 chipset) Intel Celeron 2.2 Ghz, 512 Mb SDRam, 30 Gb 7200RPS
HD.

My benchmarks are around 5000 for 3DMark2001SE and 2700 for 3DMark2003.

I have a question regarding 3DMark2001SE. The 2nd test (first game in
highres) seems to bring my system to it's knees. The framerates drop to
below 10 fps at times. What is it about this test that my system struggles
with? I imagine that it is either the Celeron or the slow SDRam that is
causing a bottleneck. All the other tests run with good to great
framerates, so I'm wondering what is different about this test. My MoBo
will accept DDR ram. Should that be my next upgrade?

TIA

Paul.