It's not GPU-native… that's a goal but it'll certainly take some time. Back when I was last working heavily on it there commonly wasn't enough vram but now there should be on most machines.

33 megapixels is not a lot. I'd consider that fast on my 9800X3D gaming machine but moderate on my older 2700X dev machine. But of course, what you consider fast depends on your computer and your expectations.

Zooming and panning is much faster on Filmulator than most other software because it caches full-res images throughout much of the pipeline. On my gaming monitor I can rapidly zoom in and out at a buttery-smooth 240Hz refresh rate.

But actually changing settings is a bit slower.

The earliest settings are the slowest to respond since they only operate on full resolution raw data, but they're non-creative, technical decisions on highlight recovery and demosaicing and such that do not need tweaking. Additionally, you get early feedback from these in the form of early-pipeline histograms interspersed among the tools, helping you tune these settings quickly.

Noise reduction adds a lot of processing time but once you figure that out the full-res image gets cached and doesn't interfere with later steps.

It has fast (~100ms) screen-resolution response to sliders in the filmulation tools mid-pipeline but it'll take a second or two for the full resolution image to process.

Late pipeline editing (post-filmulation) is near instant even for the full resolution.

So is it fast? Yes and no. But it tries to always be responsive and provide useful information as quickly as possible.