Enzotech Southbridge CNB-S1

Enzotech’s CNB series is the world’s first complete one-piece forged copper Northbridge heatsink with no interface or gaps.  It gives you the best thermal performance possible without using a fan.  The chipset is cooled to Optimum operating temperature with no fan noise or vibration. CNB-S1 can also be used for some Southbridge or VGA applications.
 
Features:
Multiple push pin locations for universal mounting on various board assembly (hole to hole distance 54.6mm and 59mm)
Formed of pure copper for enhanced thermal conductivity
Excellent surface flatness minimizes the interface between the heat source and heat sink

Specification:
Dimension 36 x 36 x27.6(H) mm
Weight 80g
Material Forged copper 1100
Base Flatness Polished mirror surface, flatness for machined surfaces are typically in the range of 0.0003" to 0.0004"per inch

More info:
http://www.enzotechnology.com/cnb_s1.htm