Not up to par: AMD phenom II x4 945/nvidia gtx 260 core 216

I recently finished my first build and was expecting good things from my system:
AMD Phenom II x4 945
Gigabyte Ga-MA790XT-UD4P
G. Skill 4 GB ddr3 1333
Nvidia GTX 260 Core 216 superclocked edition
Maxtor 6l300S0 300gb 1.5gb/s HD
Corsair CMPSU 850tx power supply
Vista Home Premium 64bit
i had originally bought a computer from cyberpower 4 years ago. after its performance deriorated i decided to reuse some of the components and build a new computer.
The problem that i see with the computer is the lack of performance that i get, i ran several benchmarks
PerformanceTest 7.0 score: 493.57 (a terrible score when compared to someone with the same components gets a score of 3007)
When i play CS source (a very simple game graphically) i get 30-40fps... i am really not sure what is the cause for the lack of performance when i invested so much money in this system.

CPU or GPU overheating might lead to throttling speed
check whether the CPU is seat porperly
i guess the GPU is just fine...
do u have tons of software running behind the screen ?
or post a task manager screen shot for us

Do you have an up to date BIOS? I get the feeling you don't and your Phenom is running severely underclocked.