There is no clear range. Some may OC higher other lower. Of course, the mobo counts a lot,but luck is another important factor.
However most Opties will break the 2.5 ghz barier that is more than enough for a dual core CPU.
yeah max setting in the bios is 258 @ muti of 11 2.835 effective and this is on the Asus A8N-Sli premium mobo the only drawback with this board is its max cpv volts is 1.55 on bios
where as in ai booster i can get 1.6 but have'nt needed to go beyond 1.48.75 ive found it to rock at 2.750 running all my benchtests so i think i keep it at that for now
getting a nice boost over the single opty 146 cabye 540
just to let you know this opty is the 175 ccbwe 0601
due to the late week i was'nt expecting such a reasonable clock