At least on the Asus 165 Hz IPS model tftcentral actually measured slightly worse (very slightly) pixel response behaviour at 165 HZ than at 144 Hz.So it looks like my XB270HU is one of the newer ones that have the 165 Hz overclocking feature. Is there any reason not to use this all the time? I assume that will also allow G-syncing up to 164 fps (seems like it at least from what I've played).
I'd probably still run it at 165.