ZDNet chart reveals what Snow Leopard can do on Macs from 2006 through 2008. Ed Bott:
This release of OS X looks a lot like a service pack. It makes some interesting architectural changes that will no doubt be useful in Macs designed in 2009 or later, but it’s not likely to make a noticeable difference for anyone with a 2008 model or earlier.
Check the chart to see what Snow Leopard features apply to your Mac.