Hi all, First post, so go easy on me please! I'm a pro photographer using a mid-2010 27" iMac (2.8Ghz, 12GB RAM, OSX 10.8.4). At this time of year, during wedding season in the UK, the iMac is getting a LOT of use and is struggling a bit under the strain. Due to the very large volumes of images I'm working on at any given time, it suits my workflow to open up 50 images at once in my version of Photoshop CS5, after their initial edit in Lightroom 4. These images are split between my two cameras; one shoots 16MP files, the other 22MP, so the files are fairly hefty in size. When working I can have Safari, Mail and iTunes open but regularly shutdown Safari and Mail if things start to get really slow. I was wondering if anyone on here could clear up a few queries of mine please (I'm not particularly a tech wizard, so layman's terms please!): - During every CS5 session, under the conditions above, my 'Page outs' far exceed my 'Page ins' and my 'Swap used' can easily go up to 8-10GB. I get the beachball regularly and although my iMac very rarely slows down to a complete halt, it can get frustrating when the process repeats itself for hundreds of images! I've read on forums that a high 'Swap used' suggests more RAM needed; would an upgrade to 16GB make much of a difference? - Before backing up/deleting unnecessary files, my internal HD can get to between 250GB-100GB of free space; would this really affect performance that much? I'm currently pricing up a RAID external set-up, so I can hopefully sort this issue out in the next week or two. - I've also read bad reports about CS5 and Mountain Lion. Do any other Photoshop users have better performance with CS6? - Are there any preferences within CS5 that allow it to work better on a quad core machine, or will the program do this automatically? After viewing various forum threads I have tweaked the performance preferences in CS5 but didn't see any noticeable difference... As my computer is an important tool of the trade, if necessary, I am considering the upgrade to the new MacPro, if it was an upgrade that would make a real difference to my workflow. Does anyone on here with more knowledge than me think it would help, based on the tech info Apple have released so far? Thanks in advance for your help.