Apples MacPro sales went down when Intel introduced Nehalem.
The "Core" based Xeon's cost about 300-500 dollars for a decent core/mhz processor.
With Nehalem (and no competition from AMD), Intel raised the prices 300% for Xeon processors. 2006 I could get a dual quad core 2.66ghz Mac Pro about 2000 dollar. The cheapest Nehalem MacPro dual core was 3500 dollars, and that was 2ghz/2.2ghz parts. To get some speed you needed to add 1000 dollars.
This killed the...