yeah its the ram most likely...
need to try to find a ram/cpu divider
its usually 1:1, but if your running 800/1066 its most likely 5/6 (im not good at math, so im not sure)
change it to a bigger divider (as in more distance between the two, so the ram runs at a slower speed)
then you'll be able to get that 2.7 ghz, and most likely push it to at LEAST 3.0ghz on air cooling, if not more..
but u gotta keep your temps in check, download coretemp, i like that one the best,
some people like speedfan (i dont trust it)
and read the readme before u use these, because some temp monitors use a little external circuit on the mobo to monitor temps, and its almost ALWAYS 10-15c lower than the actual value..
coretemp reads directly from the core
and a comfortable temperature is 60c MAX under load (although these cpus are going to probably work at 70-80c, i just dont feel comfortable running it that high. so try to keep it to 60c or lower)
(use prime95 for heating it up, like i suggested for stress test below.. it has an option to "test for heat" or something like this)
so to recap
increase the ram/cpu divider (this can be achieved by simply lowering the ram speed in bios to 667 or 533 instead of 800)
by the way, as to the guy that said "overclocking shouldnt effect internet"
it SHOULDNT =P, but unstable systems can cause all kinds of weird issues that you wouldnt commonly associate with overclocking
ask nos=P he knows all about it.... he's got a 1.6ghz overclock
oh, and once you achieve 2.7ghz
download prime95, and memtest
use them both for at LEAST an hour ,
they will let you know if its a stable overclock,
every time u bump it up (50-100mhz) u need to check these 2 programs for a bare minimum of 30 minutes to test it..
this way u can catch the errors before you burn something up