3DMark2000 is a synthetic DirectX 7 benchmark and doesn't always represent real-life performance. It's very CPU-limited so you'll need a fast CPU to max out your graphic card. This means a GeForce4 Ti4200 will probably get the same results as a Radeon 9800 Pro if you benchmark it with a slow Pentium II CPU.
I used both a Pentium II 450 and a Pentium III-S 'Tualatin' 1400 CPU to benchmark graphic cards. In any case the scores with the Pentium III-S 1400 CPU were much higher. Also cards with more MB of RAM score higher which isn't always the case in real-life applications.
Keep in mind that the 3DMark2000 score will greatly increase on cards that feature hardware texture and lightning (T&L). Back in the year 2000 only a few games supported T&L, causing the 3DMark2000 score to be less accurate compared to real world games.