GeForce 7800 GTX 512: The Quadro Cooling System
The cooling system looks heavy, so you may wonder why NVIDIA didn’t put a cross-shaped back-plate on the reverse side of the PCB to prevent the card from bending. But the fact is the cooler is actually very light despite the impressive dimensions. At least, it seemed no heavier than the single-slot cooler of the ordinary GeForce 7800 GTX.
The cooler owes its light weight to very small amounts of copper in its design. One of the few copper details is the rather thin plate that directly contacts with the GPU surface through a thick layer of gray-colored thermal paste. It is difficult to apply this paste due to its thickness but it does ensure excellent thermal conductivity. The heat is transferred from the base and is evenly distributed along the two sets of thin ribs via four heat pipes, also made of copper but coated with a thin layer of nickel. The aluminum ribs are fastened on a light-weight aluminum frame and are covered under a translucent air-directing casing. The ribs are pressurized rather than soldered to the heat pipes, but the heat contact is tight and heat transfer is good as indicated by the fact that both right and left heatsinks become very hot at work.
The frame that the rest of the details of the cooling system are installed upon has jutting areas opposite to the memory chips and, as we have said above, touches them through thermal paste-soaked cloth pads. The frame is large enough and is cooled by the fan, so you should not worry much about the thermal conditions of the memory chips.
The fan the installed cooling system is equipped with is an interesting thing, too. It is 80mm in diameter, i.e. it is the same size as standard system case fans. The wide and smoothly curved blades indicate that the fan is optimized for work at low rotation speeds. The required current, only 0.13 amperes, is indicative of the same thing, too. At 12V voltage the fan consumes only about 1.5W. The fan being of the axial design, most of its air stream is directed downwards, to the cooler’s base, and then the base with the casing make the air flow to other directions. Part of the air stream that goes leftwards cools the left heatsink and is exhausted to the outside of the system case, while the other part cools the right heatsink as well as the heatsink on the power circuit elements.
This cooling system earned a good reputation working on the professional graphics card NVIDIA Quadro FX 4500. It is somewhat more difficult to cool a GeForce 7800 GTX 512: the graphics processor works at about the same frequency as on the professional card, but the memory works at 850 (1700) MHz instead of 525 (1050) MHz. The cooler does its job well, nevertheless. We expect this cooling solution to be quiet enough and we will check this out shortly.
Like the GeForce 7800 GTX, the GeForce 7800 GTX 512 is equipped with a MIO connector for joining two such cards into a SLI pair. It also features a Philips SAA7115HL chip that endows the card with VIVO functionality.