I have an early 2009 Mac pro (2.66 Quad-core) if I get 12GB DDR3-1333 (http://www.crucial.com/uk/store/partspecs.aspx?IMODULE=CT3KIT51272BD1339) will it work ok/clock down? Are there any negatives in getting it over the recommended DDR3-1066? I thought if I get the 1333 I'll be somewhat future proof (in case I get a new Mac Pro in the next year or two). Any thoughts on this? thanks!