The cooling system of the Radeon HD 4870 resembles the cooler of the Radeon HD 2900 but there are considerable differences. The most important difference is that the heatsink is made from aluminum rather than copper. That’s reasonable since the RV770 generates less heat than the R600 while aluminum is cheaper and lighter than copper.
The cooler follows the classic design with a blower and the exhaust of the hot air out of the system case. The cooler has a copper sole contacting with the GPU die. A large heatsink consisting of thin aluminum plates locked together is connected to the sole by means of two thick heat pipes. The whole arrangement is not connected to the other parts of the cooling system. It is located within the casing and fastened to the PCB with four screws and an X-shaped spring-loaded back-plate. Traditional dark-gray thermal grease is employed as a thermal interface.
The bottom of the casing is made from aluminum and painted red. It is not connected to the heatsink or heat-exchanger but is fastened to the PCB individually with 10 screws. It is massive enough to serve as a heat-spreader for the memory chips and the load-bearing elements of the power circuit. Elastic thermal pads ensure proper heat transfer in the places of contact. The cooler uses a CF1275-B30H-C004 fan manufactured by NTK Technologies. Its max output power is 12 watts (1A at 12V), so you can imagine how noisy it can be. The fan has a four-pin connection with PWM-based speed management which has become traditional for modern graphics cards.
A red plastic casing is attached to the base. On the VisionTek card there is a sticker on the casing showing the same picture as on the product box. Club 3D just left the ordinary ATI Radeon logotype.
The cooler of the Radeon HD 4870 has a proper design. We have no doubt it is capable of dissipating 130 watts of heat at comfortable noise level.