Interesting. That indeed seems to be the problem. I didn't think that would be the case since I used what the config recommended and had ZERO gameplay problems in the form of slowdowns, hitching, responsiveness, etc. I was cruising along at a modest 50-60 FPS at 1920X1080. But lowering the resolution down to 1024X768 kicked my FPS up to well over 300 and the mouse was as snappy and responsive as I could have asked for. Annoyingly, the game itself doesn't play any better than before, and of course it looks like sh*t now. But thanks.

Strange, I have other games that run much more poorly on my system in terms of responsiveness and FPS but mouse cursor always works fine. I take it that it's something to with software emulated mouse, which may not be the norm?

Again thanks. Clearly, I need to upgrade.