Hi, I recently bought an iMac, 21.5 inch. Processor: 2,7 GHz Intel Core i5 memory: 4 GB 1333 MHz DDR3 AMD Radeon HD 6770M 512 MB I'm a graphic designer so i work a lot with photoshop, illustrator and indesign(CS5). Sometimes I need them to run at the same time, mostly with safari and iTunes open too. I find that this iMac isn't fast enough , and it even lags when i'm doing basic things in photoshop like zooming in, transforming objects, saving files, etc... I expected it to run faster. Can i solve this problem by buying extra RAM memory? I really want these programs to work fluently, because now it's just irritating me when i have to wait all the time. If yes, how much should i add?