Maybe data enough...
...I think one would be accurate by 97% in saying the G34 boards do not overclock except with software. That 3% is reserved for some ES processors on a few boards and some SuperMicro motherboards with modded bios. I am not sure if ES processors are accepted in F@H. I have seen a bias against them in doing this search. It seems that K10Stat was only overclocking a single core of the 'many' core cpus.
Then I came across this statement that seems to back-up what I just glimpsed many g00gle searchs back. "And yes some Opterons are overclockable with a custom bios if you have a Supermicro board. I have my 6128s overclocked to 2.4Ghz from the stock 2.0Ghz." The back-up statement I refer to is some SuperMicro boards can be overclocked about 12.5% if a modified bios is used.
Then following links that "shelter" had mentioned when I found that above, I came to a 56 page thread that is linked below. Because I have no intention of building such a rig, I only read some 6 pages of the thread. TONS of information. I DID come across a blurb about [H] being the place to look for the modded bios for certain SuperMicro mobos.
If you are serious about such a build the link below is like something out of a how to cookbook. I experienced some sensory overload. Almost like years ago when I went to 2cpu dot com, which does little nowdays; compared to yesteryear, when I checked about a year ago.
Building a 2P/4P; From Start To Finish - Along with PPD Benchmarks & Gallery