Oracle 12c vs 11g performance

Question

Are there any metric regarding the performance differences between 12c and 11g?
If you took a single instance 11g database server, exported the data, uninstalled 11g, then installed 12c and imported the data, would it run faster, slower or about the same.
What would you expect if you used the same hardware, exactly the same data / plsql code and same initialization parameters?
Has anyone done any sort of comparison?  OS and hardware doesn't really matter, I am just trying to get a ballpark idea.

Answer 1

It depends what "similar initialization parameters" means.
If you ran one of the TPC benchmarks with the (wildly unrealistic) settings that Oracle would use to maximize performance (in ways that no rational person would ever do for a real system), the 12c system would undoubtedly get a higher score on the same hardware (again, assuming that you're not using really low-end hardware that is close to the minimum requirements).  That just means that Oracle implemented some additional undocumented parameters that affect the TPC score by turning off tons of functionality that TPC doesn't test on (like, say, ACID compliance).  Though some of the real performance improvements might also come into play.
If you ran the benchmark with identical parameters tuned for 11g, 11g would undoubtedly win because you'd be disabling most of the useful 12c performance improvements and incurring the overhead of additional functionality.
Unfortunately, neither of those options is particularly useful in the real world.  If you're talking about TPC, what you'd really want is a "real world TPC" number where you're not running crazy configurations or a hyper-tuned system.  But no one does that for any version of any database in part because it's very subjective whether some configuration is "crazy" or whether the system is "reasonably tuned" or "hyper-tuned" or "under-tuned". 
Justin