How'd this become about me? :P
My Opty 175 is lagging behind my 3800's for one main reason. It's at my work and doesn't always have an internet connection, so sometimes it runs out of work. As far as what dual core will overclock higher than another is all a crapshoot. one week a certain batch of 170's may be golden and the next week its 3800's or 4400's. Both of my 3800's overclock higher than my much more expensive Opteron 175. Hopefully the 4800's are hitting this week.
I may have to get a 165 soon, as I hear the recent ones are getting around 2.8 on stock voltage in some cases.