The cooling system of the reference Radeon HD 4850 raises our apprehensions as it resembles the cooler of the Radeon HD 3850 although the new card should have much higher heat dissipation. Nvidia’s blunder when the company installed too weak a cooler on early GeForce 8800 GT 512MB is well known to everyone. Is the ATI Radeon HD 4850 safe? We’ll discuss the temperature factor shortly. Right now let’s have a closer look at the cooler.
In fact, the single difference from the Radeon HD 3850 cooler is the multi-blade fan and the different shape of the heatsink. Otherwise, it is the same single-slot design that seems to be copper but is actually mostly anodized aluminum. You can scratch the base to make sure of that. The only copper things in it are the core that contacts with the GPU die and the heat pipe in the base. The heatsink consists of thin aluminum plates and is quite large but it has to dissipate up to 110W of heat. The modified shape of the ribs is meant to help the heatsink do its job well: the ribs are directed away from the mounting bracket, exhausting the hot air towards the side panel of the system case where a vent grid is usually located.
The cooler is equipped with a new fan that has as many as 19 blades. This should increase its static pressure and cooling performance. The fan uses a 4-pin connection with a tachometer and PWM-based speed regulation that has become traditional for all modern graphics cards. The noise parameters of the cooler will be discussed in the next section.
The down side of the cooler is quite ordinary. The positions of the pads for the memory chips are different from the Radeon HD 3850. The elastic pads are the same, though. You can also see such pads at the places of contact between the cooler and the power transistors and inductors of the power circuit. The base forms a small needle-shaped heatsink on the face side against this spot. Dark-gray thermal paste serves as the thermal interface between the GPU’s copper core and the cooler.
The cooler is fastened firmly. Besides four poles with spring-loaded screws and a metallic X-shaped back-plate, it is secured with eight additional screws on the PCB. The metallic frame on the GPU provides additional protection.
The cooler of the Radeon HD 4850 card is quite good overall but it may not be enough for a card with a power consumption of 110W. We’ll check this out right now.