FrostyTech has posted an article on the ATI R300 Package
To put it bluntly, there is problem with the ATI R300 processor package that impacts just how well heatsinks can cool on the Radeon 9700 Pro. With the area around the R300's silicon core populated by ultra small capacitors and resistors, the manufacturer has placed something there for protection. That protection comes in the form of a 4mm wide band of copper which runs around the perimeter of the 40mm square package. It helps to prevent the tiny components from getting crushed, or the core from being chipped. This copper shim is glued to the surface of the PCB, and if it were installed flush to the height of the silicon core, it would actually be very useful.Read more
