There's an Overclocking discussion going on in a local cad.chat newsgroup I set up as a forum for those with an interest in my Computer Arcjitectire and Design class. It appears that overclocked processors may harbour subtle errors when calculating SETI@home results: Team Ars Technica Lamb Chop - Statistics and Benchmarking

Unsettling news...
The 3.03 benchmarks started to trickle in and a few results were obviously in question because they contained extra spikes or the values were ridiculous. About this time along came Roelof and the fun started - not content with my slow old ways he cobbled together some code to check the result.sah far more thoroughly than a mere eyeballing could achieve. Boy! Did the results ever give us a shock. Many of them produced on highly-overclocked processors contained errors. If you overclock there's a good chance you fall into this category. Many of you OC to the point where it locks and then reduce it a few MHz believing it to be now 'stable'. The debate about whether overclocking and its ramifications was acceptable in a scientific enterprise suddenly loomed up. It seemed that although machines completed the benchmark in seemingly reasonable times the results showed that errors aplenty had been generated in the result.sah file! So actually reaching 100% completion of a WU is not a satisfactory measure of your systems reliability. You cannot be sure that your machine is producing kosher results just because it completes WU's at a close to average time! Just because you can play games, burn CD's and run the SETI client concurrently does not give any guarantee your system is error free.

Of course, this means that if you get dodgy results for SETI then you're likely to have dodgy results for other things. It might not matter so much when playing games but it may (will!) be a big deal for other applications. Thought provoking...