I did almost the same thing. Built a 3770k with 32GB Ram, SSD which flys overall but with CS6 I notice that when working with large projects whenever I press RAM preview – it takes 20-30 seconds to just start rendering the content, when it does it goes quickly but it’s very frustrating when making lost of little changes. I ended up killing the disk cache because it was even slower (had it on a 7200 drive).
I can tell you that the I also had an ATI video card in my old rig, which doesn’t use the GPU for acceleration…nVidia “Cuda cores” make a difference. I went with a $200 GTX 660 with a good number of cuda cores and enabled the hack for GPU acceleration and it was a world of difference.
I don’t expect to get my problem solved as almost every issue I’ve ever had with AE over the years usually ends up with a non-answer or blaming my system in some way that later proves incorrect.
I agree that RAM is crucial, all 32GB gets sucked up for even the smallest HD projects, might look at getting another SSD for the disk cache as it seems like a good investment for the bigger stuff.