Thanks for your help. If only I had asked before I bought. RMA.
Worse things could happen... just don't open the (sealed,
retail?) box to try it as that may devalue the processor and
cause a restocking fee (if not already mandated by the
seller). I suppose if the return fee were the same either
way then you might as well open it and try it though it
would seem paying a premium per performance (since it'd be
underclocked to a lower speed) is not such a great value.