I've had my Mac Pro tower (a 2008 Quad Core with 8GB of RAM) for about 5 years.. used lightroom since its beginning. At first it was really fast, scrolling between photos were 'snappy' etc. Now with LR 4, using a Canon 5Dmk2, photos are taking for EVER to import, and then switching between each photo is taking a few seconds to load, and trying to zoom in and do spot removal etc is taking forever and stalls and all in all a pain. My question: Is it b/c my processor is slow? or is it b/c i lack RAM? I'm considering whether i need a 12 core mac pro tower (whatever is being released later this year), or an iMac is good but load it up to 32GB Or RAM. Of course a 12 core tower with 32gb ram is great but there's the cost issue. so. Anyhow, please let me know your thoughts!