They're both horrible laptop gaming chips but the x700 will give you better performance.

There is no graphics card to change as the graphic chips are built into the motherboard. This is common with most makes of laptop computers.

If you go to your control panel and click on display settings there should be a drop-down menu that will list the name of your graphics card

For serious PC gaming, a graphics card is a necessity. That being said, there are plenty of games which can be played with only a decent CPU. A list of older games such as Half Life and StarCraft should run well on a modern machine without a graphics card.

A computer without a graphics card will have no video output. Therefore you'd only be able to play games which do not require any visuals.

(I'm counting CPU's with graphics cores and built in chips as a graphics card.)

a game of battleship that has no graphics and only text.... assuming you have a way to input digits and a readout or Pong if you just have a oscilloscope.