Having some stuttering and issues when trying to ram preview, it only previews a few frames at a time then stops, has anyone had issues with ram preview, am i missing a setting or something. Nice new Mac Pro towers running the latest OS.
that you're doing proper RAM previews ... with the zero key or SHT+zero keys, not the spacebar ... sorry, I use both platforms, but only my fingers (not my brain) recall the Mac keyboard equivalents when I'm on a Win machine as I am now
that you're not using a codec that isn't suitable for AE work ... check Dave L.s "stock answer #1" for details
that you don't have OpenGL turned on
that your machine has enough RAM, which a new Mac pro tower should
that you don't have a ton of other RAM-intensive or processor-intensive programs and/or background processes running outside of AE
if you're working in HD with a massive amount of layers, render-intensive effects, masks, cameras, lights, shadows, etc., etc., you may be getting the best your machine can handle in that scenario
If you;ve confirmed that none of those things are affecting your previews, you may have some other issue going on that'll require more info to figure out.