I highly suggest you not worry about how big of a cooler you can get for it. A simple cooler master CPU fan for $14 down the street will fit, and with the amount of airflow, you really don't need to worry, trust me. I've seen the temps on this first hand (at 70F ambient, my quad-core 3.2GHz idled at 11C and 28C after 30 minutes at full load with above-mentioned $14 CPU HSF), and it beats out both of my cooler master cases (including a 690 with 9 120mm fans)