Intel GPU's are integrated to the motherboard. Basically if you have a read graphics card in the computer it can't be an intel. AMD/ATI and NVIDIA are the two companies that make real cards (they make integrated chipsets too). The current NVIDIA card are the 5XX series, the AMD are 5XXX series. They are very competitive to each other, so at a given price point you will have a card from each manufacturer that will be equivalent. Personally I prefer AMD cards.