Nikon View has a tendency to hang if you work too fast in it. I use ACDsee 3.1 (yes it's obsolete but it works) to review my preview (jpeg) files really quickly and I use Nikon View's thumbnail to spot out the RAWs I want to work with. From there, I select an image and press ctrl-e to open it up in Nikon Capture (which seems more responsive than Nikon Editor).
I found if you do not have ~1.5 gigs of RAM on the Intel versions, you will start swapping. I tried to get away with it with only 768 MB but you are asking to hit the swap and that's when it gets painfully slow.
Try not to ever zoom in if you have < 1.5 GB of RAM. That's a surefire way to get a nasty slow down. My guess is the problem is Nikon Capture does a true interpolation of the RAW vs a quick preview like Capture One.
I cannot comment on the Mac version. Apple vs x86 with regards to price/performance, unfortunately, x86 wins. Nikon did not do a good job in streamlining the system to be very responsive either, so you really need as much as you can get, learn the nuances to work around, and feed it as much RAM as humanly possible. Well, when Apple finalizes their new x86 backed systems, then perhaps it will be semi-smooth sailing again.
