All-In-Wonder X1800 XL: Cooling System
The cooling system of the ATI All-In-Wonder X1800 XL has been borrowed from the RADEON X1800 XL. It consists of two independent parts, an aluminum case and a copper heatsink, which have no contact with each other.
The heatsink is intricately designed to be able to cool the not-so-very-cold R520 chip and yet not to exceed the dimensions of a single expansion slot. There is a protruding spot (62x62mm big and 1.5mm thick) on the copper plate against the GPU die. A layer of dark-gray thermal paste (probably Shin Etsu G751 or X23) acts as thermal interface between them. It’s difficult to apply such paste due to its thickness, but it has high thermal conductivity indeed.
Two U-shaped heat pipes are soldered to the reverse side of that plate. The pipes are then also soldered to the ribbed section that consists of over 80 thin copper plates. This design ensures a large enough heat dissipation area at rather small dimensions but requires effective airflow since the aerodynamic resistance of the heatsink that consists of very densely placed plates, is quite high. The heatsink is secured on the PCB with four screws and an X-shaped back-plate that prevents the card from bending or breaking and ensures tight and uniform contact between the heatsink’s sole and the GPU die.
The casing of the cooler is a thin aluminum frame with a cut for the heatsink in the center and some ribbing on the sides. The whole arrangement is covered with a flat aluminum cap with some picture (it is Ruby most of the time, but each graphics card maker can use a picture of own choosing). In the left and rounded part of the case, an ADDA blower (45mm, 4.2W) is set up to blow at the GPU heatsink. The case is padded with a layer of translucent plastic on the reverse side to protect the card from short circuits. Soft heat-conducting pads are installed in the cuts in the protective plastic layer opposite to the memory chips. The pads take the shape of the surface they are pressed to. The contact is so tight that we could read pressed-out markings of the memory chips on the pads after we removed the cooler. The case is fastened to the PCB with four screws.
This cooling system proved its efficiency in our tests of the ATI RADEON X1800 XL. It is mostly quiet, but the intelligent control system may increase the speed of the fan and, accordingly, its noise to protect the GPU from heating over when there’s a high load on the card.