CPU vs GPU Workload Proportion

[Mxyl V]

Hello,

From what I've heard, Dolphin mostly relies on the CPU rather than the GPU; however, I was wondering which processing unit takes care of which aspects of the emulation (and, if/when I were to upgrade my GPU, what would improve afterward). My best guess was that the CPU takes care of the emulation by setting up a console equivalent while the GPU is used for the game's graphical aspects (such as models) and anything concerning enhancements/post processing; is that roughly accurate, or did I really miss how the program works? 
Thanks!  

[Shonumi]

In a general sense, what you describe is how Dolphin's workload is distributed. Dolphin emulates the GC/Wii CPU and DSP on your CPU. Other things like memory (work RAM, memory mapped I/O registers, and the MMU) also rely exclusively on your CPU, except where some video memory is concerned in some cases (I think?). The GPU handles emulating the GC/Wii GPU (more so now than ever with ubershaders) and deals with output to your screen. If I recall correctly, there are times when the CPU and GPU need to communicate, so one might be waiting for the other. It's been forever since I knew a super great deal about Dolphin's internals, so I might be outdated/misinformed about some stuff.

Anyway, an easy way to test if a game is stressing your CPU or GPU is to set your IR to 1x. If you can't handle that, chances are your CPU is the bottleneck (in rare cases, both CPU and GPU might be too weak to run anything, regardless of 1x IR). If you can run a game at 1x IR, the GPU will be the bottleneck as you increase the IR.

[Mxyl V]

Ah, that makes sense. Thanks!