Not getting enough juice?

[FireWater]

Hey all I have a general question about power supplies.

My setup is as follows"
ASUS A8N-E
AMD FX-55 San Diego
eVGA Geforce 7900
250GB SATA HD
DVD-ROM, CD Burner
1GB Corsair Value RAM in Dual Channel.

All powered by an Apevia 500W power supply
http://www.newegg.com/Product/Product.asp?Item=N82E16817148027

When I run 3D mark, I get a decent score, but when its compared to 100 other systems like mine, I am inbetween the -2 and -3 standard deviations of the bell curve. How can this be? Could it be the power supply does not give enough juice to make my system perform as it should? If not, what could be the problem?

I have the latest MB and Nvidia drivers installed as well.

 

[sirheck]

that psu is showing 16a and 18a for the power.
it should be enough.

what 3dmark are you running and what is your score?

 

[FireWater]

3d mark 06

I am not sure of my score because I do not have access to my desktop at this time.

 

[jaguarskx]

Your system is probably not optimized. Try installing the lastest drivers. While scan for any viruses and/or malware. Since you're doing system maintenance you might as well defrag your hard drives.