The one that hits 215 has a zalman passive NB heatsink, the 220 used the stock cooling.
I don't think active cooling is necessary if the case airflow is good. Neither heatsink was more than warm after running for a few hours.
Right now my home pc is running 215*11 using 1 512mb stick of buffalo pc3700 bh-5 (i don't recall the timings but I think its 2.5,3,3,7)
I'm still fine tuning it though, and I can probably hit 216~219 stabily, but 220 wasn't stable with any timings. The other board, I only tried 220 & 200, and they were both very stable.