I changed from the 2014 rMBP with a 3.0Ghz i7 to the 2017 MBP with the 3.1Ghz i5. Both have 16GB RAM. Everything I've found says that these two processors (I7-4578U) (I5-7267U) should have similar performance. Same number of cores, same number of threads, and same frequency. If anything the newer i5 should be the winner. But encoding with Handbrake seems to take forever with the new MBP. What am I missing?