CPU power and cost

Two different animals; you need to select either the workstation (xeon cpus and ecc ram) or desktop. Desktop boards may have some overclocking adjustments while xeon boards generally don't. The i7 950 1366 is good for desktop boards and has been as low as $199 at microcenter. It's about one fourth the cost of the top of the line 990x extreme (around $1000) and may run almost as fast overclocked.