Ubershaders got me back into playing with Dolphin. As a result, I took on a small project that I'd been meaning to do for a while.
Dolphin's input lag compared to a real Wii
TL;DR ~1 frame of video lag, ~2 frames of audio lag on my laptop vs Wii.
Numbers will probably vary depending on PC setup, controller/input method, etc.
DJ Hero is fun, but was really difficult to play on Dolphin due to input & audio lag. I ended up playing most of the game on a real Wii.
A while back I established that my TV had ~15ms of input lag and my soundbar had ~60ms. I used Rock Band's calibration tool (which is fantastic and better than DJ Hero's) to get calibration numbers for my Wii & TV (45ms AV sync, -65ms input lag). I then got the same numbers with Dolphin & my laptop (15ms AV sync, -65ms input lag). Putting all the numbers together results in Dolphin having a native 15ms input lag and 30ms audio lag, which is about 1 frame and 2 frames of lag respectively.
Plugged these numbers into DJ Hero and they worked great. DJ Hero in 1080p with headphones is fantastic.
Windows 10
GTX 860M
DirectX 11 backend
Borderless Fullscreen, no VSync (My laptop seems to force its own VSync on Borderless Fullscreen games, and it has very low input lag compared to Exclusive Fullscreen + VSync)
Cubeb audio backend
TimingVariance = 17 (Dolphin.ini setting which controls audio latency in ms, default is 40)
Real Wii Remote with Emulated Bluetooth adapter (Bluetooth passthrough is unstable on my laptop)
How Exclusive Fullscreen (Vsync off) compares to Borderless Fullscreen? I ask because Windows has this triple-buffering in windowed mode (and in Borderless Fullcreen too) that may result in increased latency.