Any way to speed up rendering?

Is there anything I can change with my Windows/Synfig settings to speed up rendering; half of the time I’m waiting for Synfig to render to canvas. What does Synfig use for rendering calculations anyway - CPU/GPU?

It’s all floating point, CPU. There’s not really any way to speed it up, short of rendering fewer, simpler, layers, offloading individual frames to different PCs or buying a faster machine.