Definitely (generally) the new chipsets such as (3 and 4 series chipset) will be much better that the 945P for core 2 duos processors. The new chipsets were designed to go with the new generation of processors (such as the Dual Cores, Core 2 Duos and Quad cores) with enhanced new features on the processors as well as on the boards. If you want to have a rough idea of the differences between the chipsets, you can have a look on the link:http://ark.intel.com/
It will give you all the information you may need about processors and chipsets and many more of intel products. It's a very nice weblink to find useful information about those products.
Also, when you speak about performance, it is very broad. There are so many factors that come into account depending on the use of the system and the environment.