It could be more problems. Is it only, when you open the Pattern Library, that it is sluggish, or if GA sluggish in general to use?
Please check, that you don't have any resource hungry virus killer software running in the background. In that case, you could try to disable the virus killer, and see if it help. In general, make sure you don't have any background monitoring software installed, that could drain your computer from resources.
Personally, I've had some strange things happening to me, that point in the same "sluggish" direction as your problem. In my case, I had bad sectors on my hardware, which resulted in very slow reading times on the harddisk. But also check you ASIO VST disk meter, to see if it peaks slowly when you access the library.