Athlon FX = unlocked multiplier

All current FX chips are unlocked.

No idea about the AM2 thing, but I would be suprised if they were locked. It's a large part of the demand for them (as small as it is).

It's not going to lose them money after all.... since it's the most expensive line anyhow.

All past, current, and future AMD64 FX processors have had, do have, and will always have an Unlocked Multiplier.

~~Mad Mod Mike, pimpin' the world 1 rig at a time

This question might be moot for a lot of folks.
Many 'daily driver' overclockers will optimise the system buss first, utilising fast RAM with low latency. In this case, even the stock multiplier might be faster than what the individual CPU can handle. So, the CPU multiplier is often run at an even lower value than stock setting, but with a much higher than stock CPU frequency. This usually results in a very fast, quiet and electrically efficient rig.
Of course, for those attempting a world record benchmark, run insane core voltages, have sufficient ventilation in their lab for the extensive deployment of free liquid nitrogen and a generous supply of dry motherboards, then the gloves are off.

And because they dominate .

~~Mad Mod Mike, pimpin' the world 1 rig at a time

actually i believe that the opteron CPU's OC higher...