This is important.
I know that Dell and Gateway used to ship, by default, with the Geforce 4 MX. It's important to understand WHAT the Geforce 4 MX is.
It is TWO Geforce 2 Ultra graphics processing units, tied together. Kind of like SLI (scanned line interleaved), but with two GF2's rather than two Voodoo2's. Each processor does "half" of the work. But it's still just a Geforce 2. Which supported DirectX 6.0. Which did NOT have a pixel shader, nor a vertex shader. So, to improve performance on the card, Nvidia put a bridge chip on it. It interprets the DirectX7 calls, and converts them into something DirectX6 can work with. On the outside of the Geforce 4 MX box, it will say it "supports DirectX 7.0".
That's like saying the US supports the International Space station. Sure, we would, if we had Shuttles that were cleared for flight. So, in reality, we ALMOST support the Internation Space station. We, like, totally support it emotionally.
A Geforce 2 MX is it's own processor. Nvidia took the Geforce 2 GTS chip, cut out cache, replaced what was left with full-speed cache (just like a Duron or Celeron chip), and sold it. The Geforce 4 MX is two GF2 Ultra chips, tied together and with a DirectX 7.0 bridge.
This means that games like Knights of the Old Republic, which make HEAVY USE OF PIXEL AND VERTEX SHADERS, will utterly saturate that Geforce 4 MX. Your CPU will be doing software shading. You don't have a hardware accelerator, you have a software shader. Even though you might select "Direct 3D device" in the menu, the computer is using the CPU to paint the pretty pictures.
A Geforce 4 Ti4200 is a "true" DirectX 8.0 card. It support pixel shader version 1.1. The Geforce 3 supports Pixel shader v1.0 (DirectX 7.0). DirectX 8.1 moves up to pixel shader v1.4.
Same thing with a "Winmodem". It's not a real modem; your CPU is doing 90% of the work. The modem is just a DAC (digital-to-analog-converter) for the phone line. Winmodems are nearly as worthless as a Geforce 4 MX.
I'm not trying to harsh you, here. There's a lot of people that bought Geforce 4 MX cards, simply because they had 128meg of memory. Which was more memory than the Geforce 4 Ti4200's 64meg (when they first came out). Your 1.6ghz Pentium4 is doing ALL of the graphics work on that game. If you buy a Geforce4 Ti4200 (64meg), you will notice an enormous boost in the playability of that game.