With my old X2
[email protected] with a X1900XT, I got 6447 with a CPU score of 2147. With my
[email protected], I got 7467 with a CPU score of 3223.
Admittedly the card was clocked very slightly higher, but the majority of the difference came from the extra CPU speed!
The GS is very poor compared to the GT, think there is a different memory bus speed and maybe even lower rated memory on some.. Think the GS uses GDDR2 and the GT uses GDDR3!
Your CPU is deffinately letting the side down there. Overclock it some and then see if your score increases.