The Community patch 1.71 is an unofficial patch, that is compiled from work of numerous NWN community members and completed by Shadooow. Patch contains thousand of bugfixes and brings into game several new possibilities, especially for module builders.
This patch is compatible with everything, it doesn't change the game version like it used to be with official patches so player without Patch can play module with Patch and vice versa. Patch also doesn't break any custom content you have already installed. Patch files has a lowest priority so anything in override, module or haks overwrites them. Therefore you can install it onto anything and you doesn't have to solve conflicts as it is with other projects out there.
Unlike other projects like CEP, Community Patch project focuses only to fixes or improvements of already existing content in NWN. There are no new unique creature, placeable or item models except few that were already present in game resources but not available in toolset.
Thus Patch doesn't slow neither game or toolset loading, it doesn't break DM client etc. It is absolutely safe.
For issues or additional questions please visit Patch project page.