all i7 and XEON nehalem processors reduce memory bus speed to 1066 if more than 1 memory module is installed per channel - so only 3 x 4 GB would run at 1333 on an i7 board holding 12 GB RAM
john, for running the special edition with some addons one sample drive should be sufficient, running the super package is not.
12 GB is always a good idea if you'r planning to arrange for full orchestra, though 6 would take you at least somewhere - example: loading every single sample from the special edition (full library) takes ~ 3.8 GB memory
christian
and remember: only a CRAY can run an endless loop in just three seconds.