i have very similar set up to u.I posted about this mobo a few months ago,didnt get much response apart from change to a 965p etc....so was surprised to see the response u got....anyway
I too cannot get over 2700 ghz,seems that this is the mobo limit
my settings are same as u ,except ram is still at 5-5-5-15,running at 600mhz(bugs me a bit cos under clocked).mobo will not boot with pci-e not in auto
not a bad overclock though for a cheap mobo i thinks......why need more than 2.7ghz? mean nothing in games,just a few extra points in pcmark05,who cares
i use my system for video encoding and what not and a fast cpu greatly increases the speed .
the OC is great 40% or so.
but i just wish i could go higher
i may upgrade to a 965p in a couple months or so
the core 2 is a beast at stock speeds so im not really complaining
3g's would be hardcore though