Number of Cores used by Excel

I know this question may be a little out there, but does anybody know how to tell excel 2010 to use all the available cores on your processor? So far, I have found it faster to set the affinity for the program to one core, and it will max out that single core, but I want it to max out all 4 cores to speed things up. I'm working with several ~2.5 million data points across 4 workbooks. Bleh! And there are graphs of the data. Needless to say, with an i5 processor and 8GB of ram, I'm still getting impatient with the wait time.

Thanks

Sam