Overview

The UE4 Documentation has been updated to be more useful (circa 4.22)
https://docs.unrealengine.com/en-US/Engine/Performance/index.html

Important settings

Make sure to perf profile under the right conditions:

Controlling Quality Settings

r.ScreenPercentage 25
r.ViewDistanceScale 0.4
r.PostProcessAAQuality 0
r.PostProcessingQuality 0
r.ShadowQuality 0
r.TextureQuality 0
r.EffectsQuality 0
sg.ResolutionQuality 25
sg.ViewDistanceQuality 0
sg.AntiAliasingQuality 0
sg.PostProcessQuality 0
sg.ShadowQuality 0
sg.TextureQuality 0
sg.EffectsQuality 0

Toggle HMD Settings: hmd vsync on/off/reset

Reference From https://answers.unrealengine.com/questions/23023/trouble-configuring-game-settings.html

Texture Quality Settings

[SystemSettingsEditor] ; For controlling system settings in the editor
[SystemSettings]
; NOTE THAT ANY ITEMS IN THIS SECTION WILL AFFECT ALL PLATFORMS!!!

TEXTUREGROUP_World=(MinLODSize=1,MaxLODSize=4096,LODBias=0,MinMagFilter=aniso,MipFilter=point)

TEXTUREGROUP_WorldNormalMap=(MinLODSize=1,MaxLODSize=4096,LODBias=0,MinMagFilter=aniso,MipFilter=point)
TEXTUREGROUP_WorldSpecular=(MinLODSize=1,MaxLODSize=4096,LODBias=0,MinMagFilter=aniso,MipFilter=point)
TEXTUREGROUP_Character=(MinLODSize=1,MaxLODSize=4096,LODBias=0,MinMagFilter=aniso,MipFilter=point)
TEXTUREGROUP_CharacterNormalMap=(MinLODSize=1,MaxLODSize=4096,LODBias=0,MinMagFilter=aniso,MipFilter=point)
TEXTUREGROUP_CharacterSpecular=(MinLODSize=1,MaxLODSize=4096,LODBias=0,MinMagFilter=aniso,MipFilter=point)
TEXTUREGROUP_Weapon=(MinLODSize=1,MaxLODSize=4096,LODBias=0,MinMagFilter=aniso,MipFilter=point)
TEXTUREGROUP_WeaponNormalMap=(MinLODSize=1,MaxLODSize=4096,LODBias=0,MinMagFilter=aniso,MipFilter=point)
TEXTUREGROUP_WeaponSpecular=(MinLODSize=1,MaxLODSize=4096,LODBias=0,MinMagFilter=aniso,MipFilter=point)
TEXTUREGROUP_Vehicle=(MinLODSize=1,MaxLODSize=4096,LODBias=0,MinMagFilter=aniso,MipFilter=point)
TEXTUREGROUP_VehicleNormalMap=(MinLODSize=1,MaxLODSize=4096,LODBias=0,MinMagFilter=aniso,MipFilter=point)
TEXTUREGROUP_VehicleSpecular=(MinLODSize=1,MaxLODSize=4096,LODBias=0,MinMagFilter=aniso,MipFilter=point)
TEXTUREGROUP_Cinematic=(MinLODSize=1,MaxLODSize=4096,LODBias=0,MinMagFilter=aniso,MipFilter=point)
TEXTUREGROUP_Effects=(MinLODSize=1,MaxLODSize=4096,LODBias=0,MinMagFilter=linear,MipFilter=point)
TEXTUREGROUP_EffectsNotFiltered=(MinLODSize=1,MaxLODSize=4096,LODBias=0,MinMagFilter=aniso,MipFilter=point)
TEXTUREGROUP_Skybox=(MinLODSize=1,MaxLODSize=4096,LODBias=0,MinMagFilter=aniso,MipFilter=point)
TEXTUREGROUP_UI=(MinLODSize=1,MaxLODSize=4096,LODBias=0,MinMagFilter=aniso,MipFilter=point)
TEXTUREGROUP_Lightmap=(MinLODSize=1,MaxLODSize=4096,LODBias=0,MinMagFilter=aniso,MipFilter=point)
TEXTUREGROUP_Shadowmap=(MinLODSize=1,MaxLODSize=4096,LODBias=0,MinMagFilter=aniso,MipFilter=point,NumStreamedMips=3)

TEXTUREGROUP_RenderTarget=(MinLODSize=1,MaxLODSize=4096,LODBias=0,MinMagFilter=aniso,MipFilter=point)
TEXTUREGROUP_MobileFlattened=(MinLODSize=1,MaxLODSize=4096,LODBias=0,MinMagFilter=aniso,MipFilter=point)
TEXTUREGROUP_Terrain_Heightmap=(MinLODSize=1,MaxLODSize=4096,LODBias=0,MinMagFilter=aniso,MipFilter=point)
TEXTUREGROUP_Terrain_Weightmap=(MinLODSize=1,MaxLODSize=4096,LODBias=0,MinMagFilter=aniso,MipFilter=point)
TEXTUREGROUP_Bokeh=(MinLODSize=1,MaxLODSize=256,LODBias=0,MinMagFilter=linear,MipFilter=linear)

Reference From https://docs.unrealengine.com/latest/INT/Engine/Content/Types/Textures/SupportAndSettings/index.html

PerformanceProfiling_CPUProfiling

PerformanceProfiling_RenderThread

PerformanceProfiling_GPUVisualizer