Well in general about 2.5ghz could be expected on stock cooling. i can get mine stable enough for a benchmark at 2.85ghz on air and am confident of about ~3ghz on water
unless you think you had to adjust the ram because of memory controller issues then i don't think there is anything wrong. yeah 3ghz is generally considered the upper limit for air and water cooled systems. though 3ghz+ is capable on phase change
i heard that they're a pretty close comparison when both at stock. e6300 oc way better, and can perform better at lower speeds. I think i should be able to get it a good bit past 2.5, but we'll see where things go from there, seeing as i can't afford aftermarket cooling.