As opposed to the PCB design, the cooling system has been thoroughly revised. As we’ve written above, no heat pipes stick out of the cooler’s casing. This is somewhat odd, considering that the new card is comparable to the GeForce GTX 480 in terms of heat dissipation. The answer is simple. Even without removing the casing and heatsink we can see that Nvidia has selected an evaporation chamber as the basis of the new cooler.
Nvidia is not a pioneer in this field because its opponent employed this solution in one of the two heatsinks of the Radeon HD 4870 X2. Later, a larger evaporation chamber was used for the Radeon HD 5970 where it cooled two Cypress cores (RV870). Sapphire also employed evaporation chambers in its Vapor-X series products.
The heatsink of the GeForce GTX 580 is designed in a similar way:
It is smaller than the heatsink of the Radeon HD 5970 but large enough to effectively cool such a hot chip as the GF110. The photo above shows the evaporation chamber in the base of the heatsink which consists of thin aluminum fins. In the bottom right corner there is a soldered opening through which the coolant was poured into the chamber back at the factory.
The operation principle of an evaporation chamber is very simple. It is in fact one large and flat heat pipe. The coolant evaporates at the place of contact between the chamber’s bottom and the GPU’s cap, then gets condensed in the top part of the chamber, transferring the heat to the heatsink fins, and then flows down the capillary surfaces to start the whole process anew. Since there is a vacuum inside the chamber, the coolant begins to boil at a lower temperature whereas the small distance between the surfaces that receive and give off the heat accelerates the whole heat transfer process. An important advantage of an evaporation chamber is that it is compact. There is no need to lay out a bunch of thick heat pipes as in the cooling system of the GeForce GTX 480.
The downside of this design is that the top sections of the heatsink fins do not heat up much because they do not receive any heat directly, but the higher efficiency of the chamber design should make up for that. We’ll check this out in the next section of our review.