I was thinking about getting an ECS K7VZA and Thunderbird 1.1Ghz from here. Next to it, is a link to a "CPU safety shim". I only know about these things from what I've read on the internet, as I've never installed a socket CPU before. How useful are they? Is the risk of the CPU 'cracking' a perpetual one; or only one during installation? I plan to leave my CPU on the mobo permenantly after I install it, so would it be useful for me to get one? Thanks.