CACJEs are pretty good OC'ers. Not as good as early CABNEs or later CABYEs, but almost there. I'm starting to think that this Opteron craze is not an effect of conspiracy theory, but a result of their improved manufacturing. These chips tend to show very uniform performance trend - clocks extremely high at or near stock voltages, but once they pass certain thresholds it gets very hard to raise the clocks even with some massive voltages. From my observation, decent single-core Opteron steppings have been found to be:
CABNE (~053X) -> CABYE (0540~0544) -> CACJE (0545~ ) <--- Something like that
But as the manufacturing matures, binning must be improving, too. While CABNEs were found in various models of Opterons (144,146,148,150) and reached >3GHz air, CABYEs (which clocks about the same as CABNEs) are mostly found in 148s, and some among 146s. CACJEs don't clock as high as the previous two - exceeding 3GHz is probably a no-go, most likely 2.8~3.0GHz max, and are mostly found in 144s/146s. Anyway you look at it, it seems like AMD has a quite bright future for the time being.