So I've enabled OpenCL hardware acceleration via Edit > Preferences > Performance, yet whenever I render an image, it seems to be using the CPU almost entirely, with no GPU help whatsoever:
Is there something I'm missing? I'd like the GPU to be responsible for the rendering, not the CPU.
It is working. You can see the spikes of GPU activity and a reduction in CPU activity at the same time - that's the actual rendering of the focus stack. The rest is probably loading (decoding) raw files. Are you working with raw files?