With the major update of PCMark for Android benchmark app Futuremark adds another new feature, the ability to compare scores across Android versions as OS updates can breathe new life into older devices.
http://www.notebookcheck.net/Futuremark-Android-performance-of-LG-Nexus-5-and-Samsung-Galaxy-S5.180094.0.html
So, The Nexus 5 with 6.x beats the Samsung Galaxy S 5...interesting.