MonsterHardWare has a review of the Swiftech MCX462-V HSF, this is a good HSF for those still using Socket A.

The Helicoid pin design increases surface area of the pins. This increased surface area creates a more effective mechanism for heat dissipation. Also these pins are aligned in concentric rows which are bent at different angles. Swiftech says ?The spacing and angles between the concentric rows has been precisely calculated to optimize cooling and reduce noise at air flow levels as low as 22 CFM and 23 dbA.