After removing the rather dinky stock ATI fan-heatsink, we cleaned the R300 core of all the residual yellow thermal interface pad and applied a small amount of the white silicon thermal compound Zalman include in the package.

ATI's stock cooler as you are probably already aware, offers sufficient cooling by way of a thermal interface pad, but doesn't actually make direct contact with the silicon core. The shim around the edge of the processor package is just slightly higher than that of the core so a flat base on any heatsink will cause the same problems.

The original ZM80-HP mounting base was designed with a flat bottom, but with the revisions and other improvements Zalman have made to the ZM80A-HP this problem has been addressed. While the ZM80-HP could be used with a Radeon 9700, I'd really only recommend using the updated ZM80A-HP model we are testing here.

The machining around the outside of the of the extruded base is very shallow, not more than maybe 0.003", but offers sufficient clearance for it to contact the R300 core. We tested this out with very small amounts of silicon to see where the imprint landed, and the silicon did indeed make contact with the aluminum.

Some Radeon's (or for that matter nVidia-based cards) will come with pre applied BGA ramsinks which can be difficult to remove. Since the base is 15mm thick you have at least that amount of space to work with on the rest of the card. Any ramsinks falling under the Zalman heatsink have to be smaller than 15mm tall or the assembly will not sit properly.

As with other video cards on the market, the ATI Radeon 9700 uses closely spaced off-center diagonal mounting hole. After selecting the right sized base mount we installed it on the card after fitting it into place. The two little metal arms are adjustable so you can move them around, and Zalman include a small screw driver so you don't even need to have any of your own tools handy to make the adjustments. It's important to get the base mount assembly centered on the GPU and straight, and then tighten the little screws which hold the arms in position.