Nice find. Good overall review.
There are a few things that annoy me though.
They don't mention anything about timings other than primaries, which means they used auto for everything.
That means subtimings will be affected, which makes the comparison somewhat inaccurate, & explains why the 8 GB is sometimes "slower" than the 4 GB...very likely different subtimings are being applied.
And this part confirms my suspicions they were n00bs:
If we even waved a hand near our Asus P5Q Deluxe when it had four DIMMs sitting in it, it was enough to make it blue-screen or jitter.
Retardedness.
They are lucky they got a board like the P5Q that is actually easy to run 8 GB in...