3.3 4 core, nvida Gt8600 vid, wind 7, 4 g ram and cable not thinking so
Think what you like, cable can have routing problems too. To check it out download pingplotter
HERE. After downloading and installing copy and paste this address in the top box 206.16.60.39 and set it to ping every second for a couple of minutes. Any "red" showing is bad. Paste a screen shot here for more detailed info.
The 8600 video card is the old generation, I changed mine out two cards ago. Also 4 gig or ram is nothing on a Win7 machine. Windows uses up a good chunk of that all by it self. You could run a Dxdiag report and post the first third here. Maybe someone will spot a problem or two in how your rig is set up. If you don't know how to run the report, you can check
HERE for instructions.