For any ram you are considering, do your own homework.
Go to the ram vendor's web site, and access their configurator.
Corsair, Kingston, Patriot, OCZ and others have them.
Their compatibility list is more current than the motherboard vendor's QVL lists which rarely get updated.
Enter your mobo or PC, and get a list of compatible ram sticks.
Here are a few links:
http://www.crucial.com/index.aspx
http://www.corsair.com/configurator/default.aspx
http://kingston.com/
http://conf.ocztechnology.com/index.php?c=1
Cpu performance is not very sensitive to ram speeds.
If you look at real application and game benchmarks(vs. synthetic tests),
you will see negligible difference in performance between the slowest DDR2 and the fastest DDR3 ram.
Perhaps 1-2%. Not worth it to me.
Don't pay extra for faster ram or better timings unless you are a maximum overclocker.
The P6T bios will select a running configuration if you leave everything on default or auto.
Even if you wish to overclock a bit, the bios will set the ram as best it can. For a simple overclock to 3.0 just raise the BCLK value from 133 to 150,and leave the ram at auto.