Cooling System Design
Radeon HD 4770 cooling system uses a well-established solution with a radial fan that removes hot air outside the system case. We will not dwell on its detailed description again, because we have already discussed it multiple times in our previous articles. However, there is one thing that we would like to draw your attention to.
As you know, starting with Radeon HD 2900 ATI have been using high-quality but rather noisy fans from NTK Technologies for their reference cooling systems. These fans became known for a typical crackling of the bearing even at low rotation speed. This is why these cooling solutions have been criticized fairly multiple times by users seeking quiet comfort. Finally, Radeon HD 4770 has come to turn things around here.
As you see, the new cooler uses a Delta Electronics fan. Moreover, our regular readers should know the BFB1012 model very well, because Nvidia use exact same fan for their reference coolers, and they are known for being pretty quiet. Therefore, we have every reason to expect Radeon HD 4770 to work very quietly, too.
Like in most similar systems, the heatsink is made of thin aluminum plates and uses two heatpipes to connect to the cooler base, which is made of aluminum. The contact area is covered with a layer of traditional dark-gray thermal grease, while the rest of the base is covered with clear protective film. They may have done it to eliminate the possibility of a short circuit. However, I can hardly imagine how the cooler base could shift far enough to short circuit any of the PCB electronic components without ruining the fragile GPU first. The base is attached to the card PCB with four threaded spindles, spring screws and an X-shaped metal backplate. As usual, hot air goes through a number of vertical slits in upper part of the card retention bracket: despite being a budget solution, Radeon HD 4770 uses a two-slot cooling system. It is not very common for a sub-$100 graphics adapter, but if it proves worthy in games, we will be able to forgive it. :)
The memory chips are cooled with a special shallowly ribbed metal plate that contacts GDDR5 chips through rubber-like thermal pads. The specifics of its retention also help prevent the bending of the graphics card PCB.
This cooling solution looks pretty promising, primarily due to Delta Electronics fan. However, if the rotation control system is set up too aggressively, we won’t achieve the desired level of acoustic comfort. However, let’s not speculate anymore and check things out in real tests.