Thanks! Ok, I need to figure out how to make it quicker on slower machines. But till then I think the difference seems to be the graphics cards, and windows version. I think it might be the slow graphics card on your older machine. Have you tried to run on Chrome on the older one, and both on Firefox and Chrome, you can enable / disable hardware acceleration. I find that depending on your hardware , the hardware acceleration helps or hinders the browser.
Titan XP is pretty fast. It's not that much slower than the 3070 - I don't think it's the graphics card. https://www.gpucheck.com/compare/nvidia-geforce-rtx-3070-vs-nvidia-titan-xp/ - Also, before anyone comments or makes snide remarks, I was gifted the Titan XP by a friend who was part of the nVidia academic elite (he got several).
That said, I can try other browsers and enable/disable hardware acceleration on both and report back.
Thanks for being an open minded developer and not blaming everything on old computer :)