I've been having issues with GX being really sluggish these past few months. It got really worse this past month and I tried everything from reinstalling to clearing the cache. Then last night, being fed up, and nearly switching over to Firefox, I decided to clean out my bookmarks. I found that I had some duplicate ones and read that those could potentially cause browser issues due to corrupt data. So I went ahead and annihilated about 70% of the bookmarks I had saved, and lo and behold, it sorted out my issue.