That ping depends on the framerate. If you have 60 FPS, the minimum ping is going to be 1000/60 = 16.7 ms, since packets are processed in the Update() and responses won't be processed until the following update. Not sure what you mean by "polling at 0.75s intervals". Pings are checked every couple of seconds. Spamming ping requests isn't a good idea, especially considering that if you have a server in north america and a player in Australia, you can expect pings that are higher than 750 ms.
