People have to realize that 3Dmarks03 is also a composite of both GPU and CPU scores. Since the AThlon 64 is such a powerful and high performing CPU, it is very much onpar with many of the P4EE systems we see. (Like the ~3500 scoring Inspiron XPS).
If eMachines were to upgrade to Radeon 9700, I would have little doubt that it would be comparable to a high end Dell or whatever DTR. But as is, eMachines systems I believe are Arimas, and they have soldered on (unupgradeable) GPUs.