Cheers for the reply. For portal 2, it’s not a demand issue – performance indicator even on 120hz at maxed out resolution gives 60-80% performance headroom on my system and doesn’t drop any frames. Closer to 90% if I drop everything to mins (72hz, lowest resolution).
Actually, maxing everything out makes things seem a bit smoother. I’ve discovered if I move my head slowly, the tracking mostly keeps up and portal 2 is playable (the main reason I got vorpx). Now I’ve figured out a way to manage it, it’s an absolute delight starting from the beginning – thank you for Vorpx, it’s ace.