XFX 9800 gtx+ XXX edition performing too slow

Hi!!

I just recently bought a xfx geforce 9800gtx+ xxx edition.
My machine config is

intel core 2 duo e 6300
intel desktop board 965p
3 GB ram
creative xfi fatality sound card
cooler master 600W PSU

The PSU I have has only one 6 pin connectors, so I bought a molex to six pin adapter for the second (I connnected the molex sockets to plugs from 2 different power rails).

The manual of the card says that you an adapter should not be used.

When I Ran 3d mark vantage it gives me a result of 5000 something 3d marks in performance settings at res 1280 x 1024.

Also the games are running very slow and there is no increase in frame rate when I decrease the resolution. The peak frame rate is around 30 and usually it stays around 17-18. Even my laptop with an 8600m gt gives better framerates.

. Evga precision repots that the card is running at 775MHz cora and 1890 MHz shader clock 1123 MHz memory which is normal.

I cant figure out why the card is giving such slow frame rates. All over the net I have read the 9800 gtx+ performing a lot better.