Content originally posted in LPCWare by wellsk on Thu Jan 30 21:08:21 MST 2014
The LPCXpresso packages only contains the filtered code needed to make the project run, while Keil/IAR packages contain all the project code plus all the unfiltered 3rd party code provided by 3rd party developers.
For example, with FreeRTOS - only the necessary files to make the project run in that configuration for FreeRTOS are in the archive. However, the Keil/IAR packages also contain all the other FreeRTOS files (all port files, heap files, etc.). This also applies to LWIP, uCos-III, CMSIS, etc. This is the reason the Keil/IAR packages are bigger.