HAL9000

Hi all.
I have just installed a pc with windows vista 64.
this is my hardware and the score of vista performance monitor


Processor Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz || SCORE: 5,9
Memory (RAM) 8,00 || SCORE: GB 5,9
Video Card NVIDIA GeForce 8800 GTX || SCORE: 2,9
Memory video 2814 MB|| SCORE: 5,9
Primary HD 434GB free (466GB total)|| SCORE: 5,9

As you can see all the score are 5.9 (and thats good) except the
preformance for windows aero that is only 2.9 and i think it's strange
because i have a geforce 8800 GTX!

Is there something wrong? The driver of the video card is updated.
Someone can help me to fix this problem?
Thanks a lot