[XF] GeIL DDR3-1066 CL6

[Rone]

You have to admit though, PC8500 at 6-6-6 isn't exactly ground breaking

For early DDR3 it's pretty good. Standard DDR3 with 6-6-6 timings runs at 400MHz (PC3-6400).
Don't confuse this with DDR2. You should compare it like this:

PC2-6400 (400MHz) with a CAS of 5 (like early DDR2)
1 clockcycle equals 1/400,000,000th of a second or 2.5ns (nanoseconds)
A total latency of 5 × 2.5 = 12.5ns

PC3-8500 (533MHz) with a CAS of 6
1 clockcycle equals 1/533,000,000th of a second or 1.875ns
A total latency of 6 × 1.875 = 11.25ns

As you can see the DDR3 module has a lower latency. But that's not even the most important benefit. The real benefit lies in the bandwidth.
DDR3 will scale all the way up to PC3-12800 (12.8GB/s) and even further. The highest DDR2 ever managed was 11.7GB/s and that's DDR2 at 732MHz (PC2-11712).