Performance degradation after switching from 4.7 to promoted 4.8 branch

I’ve been doing some profiling of standalone builds of our game over the last few weeks.

I’ve noticed steady performance improvements as we did some foliage optimizations, switched to 4.7, and turned on Distance Field Shadows. However, we just integrated the promoted build of 4.8 in GitHub this week, and we’re seeing it’s anywhere between 3-12% slower than 4.7 was. I’m curious as to why performance went back down.

See the chart below – the negative numbers you see on the right side are comparing the “UE 4.7 w/ DFS” row to the “UE 4.8 w/ DFS” row.

Do we know the reason for this slowdown? Do we know if performance will go back up by the time 4.8 is released? Is it related to this fix - Distance Field Shadows cause artifacts on certain types of meshes - Rendering - Unreal Engine Forums ?