jinhim wrote: ...I work with many effects and find my gpu processor has a large amount of headroom but GPU memory is maxed out when I render and export.
I've read that the GPU speed improvement is potentially double with the 5600M, will I see a speed boost if I upgrade to identical machine with the 5600 M ?..
Render and export are two different things. Rendering is translating edit directives and effects to render cache. For an unrendered timeline being exported, rendering is doing that translation on a few frames before handing it to the encode phase.
In general a faster GPU will not help encoding. It might help rendering -- IF the effect is highly GPU-bound. As a generalization effects use the GPU but the split between CPU and GPU varies. In the case of Neat Video the user can actually adjust the CPU/GPU split. On an 8-core machine, setting Neat Video to all GPU doesn't make it that much faster.
You can help characterize this by turning off background rendering, delete render files, select all timeline clips with CMD+A, then time with a stopwatch the render phase when you do CTRL+R. After the timeline is fully rendered, export to your preferred format and time that. This will give you a very rough idea of render vs encode time.
After rendering the timeline, try this export preset: File>Share>Master File>Settings, Format: Computer, Video Codec: H.264 Faster Encode, Resolution: 1920x1080.
The 5600M is a nice upgrade and a useful option but I'm not sure it will totally transform a performance issue. The Apple Silicon Macs will be out soon and might have significantly better performance. Supposedly a 12-core 13" MacBook Pro will be released this year, which might give the first hint. I don't think the 16" MPB or iMac will be released until next year.
The Apple Silicon SoC (System on a Chip) apparently combines both CPU and GPU and also adopts a new architecture called "Tile Based Deferred Rendering". It has the potential of being much faster than prior approaches, assuming app developers properly leverage that. Fortunately Apple makes FCPX so we can expect very early adoption of this improvement on the new machines.