I'm new to the Cooling forum and I see the SF2 recommended here over other alternatives. Having tried the SF2, along with other fans, I don't think it's a very impressive product. Not that it ultimately doesn't cool well; it does, but that comes at a relatively high cost with respect to the annoyingly high-pitched "whiney" noise generated by the fan at high speed. Nor do I think that its CFM rating is realistic, as I experienced no change in load temps after I switched to the much quieter Panaflo U1A. A Tornado lowered my temps a bit over the U1A and the SF2, so it's not as if my SLK-900a couldn't benefit from greater airflow. I guess I'm puzzled as to why the SF2 seems to be the fan of choice for many forum participants.