Techiton

In a performance comparison between Intel's latest Quad Core Core i7 processor and a two-year-old Nvidia graphics card - GTX 280, Intel have released that their CPU can't match the graphics chip's parallel processing performance.

The article in ComputerWorld states that on average the Nvidia GeForce GTX 280 was 2.5 times faster than the Intel 3.2GHz Core i7 960 processor, and more than 14 times faster under certain circumstances.
The comparison by researchers was designed to test the parallel processing capabilities of the chips.
As its name suggests, parallel processing involves tackling multiple tasks simultaneously as opposed to serial processing, which requires handling tasks in sequential order.
GPU (Graphics Processing Unit) has many cores (GTX 280 has 30 cores) that are used to draw graphics on the screen but the CPU (Central Processing Unit) has fewer cores (Core i7 has 4 cores). Hence the more number of cores helps in parallel processing.

Source: Computerworld.com