@Wlodek Regardless of what you may read into that statement XD3 is currently only available for Fuji X-Trans images and if or when it will becomes available for Bayer images of one sort or another, and what it may or may not do to memory (VRAM) usage (which could never be as bad as what AI is doing) or the quality of the noise reduction or the affects on processor usage, I cannot say.
But over in AI Masks not working in PhotoLab 9 with NVIDIA drivers (Windows) - #11 by BHAYT I did a test, sadly the images were not images with a high ISO but the timings are interesting.
Please remember that XD2s is not XD2s when applied to X-Trans images, it is XD so there can be no current comparisons between XD2s and XD3 exports created from X-Trans images because XD2s does not exist for X-Trans images and XD3 doesn’t exist for Bayer images!!