I have a XPS720 with all the bells n whistles. Have 1 Nvidia 8800 GT, would it be wise to add another and go SLI ? Also would a XFX SLI bridge strap work ? Have 4 Gig Ram, 750W power supply and 28" monitor. Usuall run games at 1600x1200 res. Everything runs good I just want a little more bang.