In Windows 7 you will no longer need a graphic card to render any 3D-application, hence you can boot your system without any graphic card. The CPU will do all the work! The new technology that makes all this possible is called “Windows Advanced Rasterization Platform” 10.

The minimum requirement for WARP10 is a 800MHz CPU (MMX or SSE is not needed). Direct3D 10 and 10.1, up to 8x multi-sampled anti-aliasing, anisotropic filtering and all optional texture formats will be supported.
Obviously your overall performance will not be as good as with a graphic card.

Windows 7 backwards-compatibility!

This is a benchmark of Crysis (800×600 with lowest quality settings), using WARP:

Link to picture

In comparison to the graphic card benchmark:

Link to picture

The average frame rate is pretty low overall, you will not be able to play games with a low-end CPU for sure. This won’t replace graphic cards, but might come in handy in the future. I also like the idea to boot a PC if your graphic card is broken or whatever.

Another new technology that will be included in Windows 7 is Direct3D 10Level9, that will allow you to run DirectX10 Games with a DirectX9 graphic card. Yes you read right, but it will not run as smoothly as it could. This is getting introduced to establish a certain level of backwards-compatibility.

Sources:

Slashdot

istartedsomething.com

• 
  Black Ops 2
• 
  Halo 4
• 
  God of War 4
• 
  Crysis 3