all right so when i got my powerbook awhile back i had it BTO with the 1 DIMM of 512 RAM, figuring that i could upgrade it later on from crucial. i have found, however, that 512 MB of RAM has been essentially enough for most of what i do. the powerbook slows down alot with stuff like iDVD and VPC and iMovie, but would this be more an issue of processor or RAM? the system moniter shows that i usually have between 50 and 25 MB of RAM free on a typical basis. So....what do you think? would it be worth it to me to get another 512 stick?