This is the exact same issue I am currently experiencing, both in Sunshine AND the Galaxy games. It gets especially bad when going near lots of npc's & water. Not sure if I should open a completely new thread or add my information to this thread seeing as this thread is still fresh.
System Specs:
OS: Windows 10 x64
Processor: AMD FX 6300, Six-Core, 3.5Ghz
Graphics: AMD Radeon R9 200
RAM: 2x4GB Corsair Vengeance DDR3
Dolphin: 5.0-8743
System Specs:
OS: Windows 10 x64
Processor: AMD FX 6300, Six-Core, 3.5Ghz
Graphics: AMD Radeon R9 200
RAM: 2x4GB Corsair Vengeance DDR3
Dolphin: 5.0-8743