This was even more evident with the introduction of AMD's Thunderbird CPU as it would shatter under the weight of installing and removing heatsinks. With the invention of better coolers, shims are not really needed on PIII processors. However, they are still a safety feature you should consider using with the Thunderbird and Duron processors to prevent damage. Although CPU shims have helped us greatly, careless users have been known to short out AMD processors with electrically conductive shims.
Many people are just plain careless but accidents do happen.
I no longer recommend any shim that is electrically conductive , they are just too dangerous to use. Now there is a new shim on the market that is also non conductive. This one is from CPUfx and is called the DTS440. The answer is yes. I tested it myself with an Ohm Meter and it shows zero conductivity.