I'd go for CN-Lite, AeonCoin for example. There the CPUs' advantage over GPUs is max. With a scratchpad size of 1 MB per thread you can start 32 threads on your 2 socket system and the data still fits into the L2 cache of your Opterons 6376. When you activate double-hash, you can still run 32 threads, filling the L2 and L3 victim cache for the last extra percent of performance. "Bulldozer was without doubt an unmitigated failure" (Andrew Feldman, Corporate Vice President and General Manager of the Server Business Unit, AMD), but at mining CN, it is a beast!