I have a PowerSpec B830 and am interesting in upgrading the graphics card. I was told by technical support that I shouldn't go with a card that requires more than 450 watts. Can someone tell me why this is? I was hoping to get a 650 watt power supply. Also, my current video card is a GT 630, which as no PCI connectors. Can I upgrade to a card with connectors? IF so, is it clear where they connect?