I've had my 2018 13" MBP for a few weeks and love it but one thing bothers me. I did a clean install of Mojave and notice that my 2015 15" MBP launches applications faster than the 2018. The difference is not great mind you, but the 2018 SSD is benchmarking at 2800 read speeds while the 2015 comes in at 1800. Both are 512GB SSDs. Any ideas? Thanks!