I have a scene that I'm trying to render (Macbook pro 16'' with 2.3 GHz I9, 5500M AMD with 8 GB of memory. The issue that I'm currently running into is that it seems that cycles with the CPU is 2x faster than AMD prorender with the GPU. Is there some settings that might speed up the render time with AMD Prorender? If not, then I will obviously just use cycles.
Yep it slower, I raise it several times on this forum.
Check out new Otoy Octane X (open beta), they have rewritten whole Engine for Mac, works perfectly well from first release
Cost is 20$ per month. Yes they have blender version as well (you actually download blender from them with Engine integrated). The new Octane X is rewritten on Metal API which means its going to work on Apple Silicon chip as well. Also its going to work on iPad, and iPad can help render (slave mode) for laptop (this feature not released yet).
When you buy it you have to download two things:
Octane server - login there
Octane Blender - use it while Octane server running in background.
Once you switch to Octane in blender you can setup shaders in similar to Cycles way, shaders it self are nicer (as for me), for example you can do Ray Dispersion (for glass) with one premade parameter. This quick test I did in Octane - iOS messages icon 3d by Denys Kurnosov on Dribbble
Also I measured Octane on my Vega 64 vs Cycles on 8 cores CPU, Octane was 4 times quicker.
AMD pro render hard to use for anything, it's crashing or rendering slower with artifacts for years now.
That's too bad , I was hopeful for AMD prorender.
So beyond if CPU + cycles if quite good (which I'll take your word for), isn't rendering via GPU supposed to be much faster than CPU?
Yep generally GPUs are faster for this kind of tasks. But in case of MacBooks the difference between mobile GPU and i9 will be smaller than a fullsize desktop GPU and i9.
Some render engines are even advocate for CPU only – Proudly CPU Based | Corona Renderer
I'm not sure how to read "with one year of maintenance" in octane x announcement. Does that mean I get updates for 1 year, or does that mean that the software deactivates after a year.