You're right April, the smudge tool is one of the more memory intensive tools in PS. This is because you are actually changing ALL of the pixels under the brush as you move it along. The larger the brush, the more memory is hit. I get lag time with my tablet but learned to move along at a smaller more steady pace. It's really bad when you try to work like you would in traditional media like "oil paint" (which is one reason i always wanted to get the app Painter)

Huck, at least you know it's not something you're doing wrong...

:)
retrocity