The bulk of the performance gain came from a fresh OS install as well as a new install of F1 2016. Hallock discovered that this particular game stores hardware configuration settings in the Steam Cloud and that the file doesn't get updated when you reinstall the game from the same Steam account on a diferent PC. Other than this really weird cloud syncing bug with F1 2016, the bulk of the performance boost is achieved by clocking the DDR4 memory at 2933MHz instead of the 2133MHz used in the base case.
Other minor gains are achieved by enabling the High Performance power plan in Windows 10 and disabling the High Precision Event Timers (HPET), although the latter needs to be enabled for Ryzen Master overclocking to work so he reactivated it for the other data points. Overclocking the Ryzen 7 1800X to 4.1GHz for all cores yielded some more gains and Hallock also discovered F1 2016 viewed Ryzen as a 16-core CPU so he edited the game's configuration file to change this to eight cores. This also resulted in a couple more frames per second.
You can read the full piece over here. AMD also promises it will issue microcode updates to motherboard makers in May, these will increase support for overclocked memory configurations with higher memory multipliers.