Has anyone had any experience of upgrading one of the old white iMacs to a SSD? I use mine mainly for iPhoto and browsing and it performs ok at the moment, so I'm hoping an SSD will give it another couple of years life while I save for a new 27 incher. However I'm aware that the machine might not be be able to keep up with the best SSDs so I don't want to waste spending extra on a fast drive I won't be able to take full advantage of. Any advice appreciated. Chris.