The I7 improvements are due to the dedicated graphics chip, most likely. Not only does the main proc not have to do the graphics anymore but the dedicated chip would do it faster and have faster dedicated video memory.
I am curious if any of you have been watching your heat? In this situation (security cams) does the I7 run cooler because the proc isn't maxed, or hotter because of the GX chip/ram? Or about the same ?
Core I7 Mini, 512GB SSD/2x Core2 Duo Mac Mini/PowerMac 8500g3/B&W G3 with G4 500 processor, iPhone, iPad