For reference, here's what the current (CPU-Z validated) OC records look like:
http://valid.canardpc.com/records.php (it's pretty safe to assume most of these used LN2 as well)
How, under the current laws of physics, did someone manage to squeeze 8500MHz out of a Celeron D????
It's based on Pentium 4 core which was extremely overclock-able, plus it's a single core, which makes it easier to get to that stable enough for a screenshot state.
It's too bad they haven't included actual performance comparisons. The Celeron (from '06) running at ~8GHz will most definitely be outperformed by any modern i7 running at stock speeds.
In what kinds of tasks? Single-thread performance has increased very slowly since the Core 2 Duo era. 8GHz is blazing-fast, even for an "old" processor.