Did you ever wonder what our benchmarks are for the time and memory requirements in Zcash for generating ZK Proofs?
Here are two charts of that comparing our first alpha, our 1.0 Release, and our latest master branch. Enjoy!
I wish that the total wall clock time to send a shielded transaction on my MacBook wasn’t over 2 minutes, but it consistently is 
What other cpu / memory / swap load does your Macbook have? Does it have an SSD?
it takes about the same amount of time no matter what the load is, I think its just its memory bus being slow or something