Generation is a term that we use to mark the micro-architecture that is being used in the processor. Right now are 3rd generation Intel® Core™ processors are our current generation of processors. The best way to understand the differences is to simply look at what you are going to be doing with the processor and compare the processors based on that information.
- Increased integrated graphics performance especially in mobile CPUs. The "GT3" version of the iGPU will be exclusive only to mobile CPUs. It will have 40 shaders which is 2x more than in the desktop version. That can mean a potentially large increase in graphics performance.
- Lower power consumption.
- Increase in CPU performance likely to be relatively small; between 6% - 8% assuming the same clockspeed.
No solid info will be available until the Intel's NDAs expire; Non Disclosure Agreements. Probably will not happen until June which is when Intel is expected to officially announce the release of Haswell at one of the major electronics convention.
Well The letest are the 3000 series from intel and the x300 series from AMD x being core number on AMD chips code names Ivy Bridge for Intel and Buldozer for AMD. Just put these into Google you will get more info than you want.