High Performance Heatsink Reviews

New flagship heatsinks Thermalright SLK-900-U and Zalman CNPS-7000, already hot topics in the the SPCR forums, are beginning to get review coverage. Can they allow even slower, quieter fans than silent pc'ers are currently using?

Thermalright SLK-900-U reviewed at Overclockers.com, Systemcooling.com, hartware.net (german), and Nexushardware.net
Zalman CNPS-7000 reviewed at Casejunkies.com