Questions about checksum feature in 9.3

I am getting a new server ready for production and saw the release note on the new checksum feature. I thought it sounded like something we might want, and then after reading realized we have to initdb with the feature on. I figured I'd better check into it a little more since changing later might be a bit of a hassle and found notes on getting a vectorized version running for better performance.

My attempts to compile it vectorized on OS X seemed to have failed since I don't find a vector instruction in the .o file even though the options -msse4.1 -funroll-loops -ftree-vectorize should be supported according to the man page for Apple's llvm-gcc.

So, has anyone compiled checksum vectorized on OS X? Are there any performance data that would indicate whether or not I should worry with this in the first place?

So far we are pretty happy with the performance of 9.2.4, but have noticed a few situations where it's a little slower than we might like, but these instances are rare. I'd accept a small performance hit if we can get better reliability and awareness of potential problems.

Thanks,
Kevin