Thermalright SI-97 Heatsink
 

Definitely nothing to block the airflow through the fins. The SI-97 is fairly large, but with its design, it will fit nearly all Athlon XP based motherboards. According to the Thermalright site, the only board at this time that has been determined not to accept the SI-97 is the Gigabyte GA-7N400 Pro2.

http://www.ocia.net/reviews/si97/page1.shtml