Well, in the PassMark cpu benchmark, my cpu (Intel Core i5-4690) ranked 47 out of all CPUS, 2,214 out of the top ~2,600. I highly doubt thats the bottleneck
http://dwarffortresswiki.org/index.php/DF2014:System_requirements#RAM
"The most important thing to the performance of the game, however, is undoubtedly RAM latency—the amount of lag the RAM has when working. Dwarf Fortress works the RAM every single frame for every single creature, every single item, every single piece of liquid, the temperature of every tile—you get the picture. The gigantic amount of operations working at the same time—which any current processor could handle much faster than what you see—is primarily bottlenecked by RAM latency and RAM speed."