How many people can you *see* simultaneously out of those 300 at the same time?
Depending on how you setup your client (overview and such) up to every single one of them. That's not in the sense of rendering all these players as 3d models in full detail of course, but clients are being updated about state of other entities present in the same grid (a grid cell is ~300 cubic km large and battles happen over 100-200 km distance... or sometimes if the sides involved feel suicidal at 10-20 km or less)
Re: PvP and faulty thinking - How to learn all the wrong lessons
Depending on how you setup your client (overview and such) up to every single one of them. That's not in the sense of rendering all these players as 3d models in full detail of course, but clients are being updated about state of other entities present in the same grid (a grid cell is ~300 cubic km large and battles happen over 100-200 km distance... or sometimes if the sides involved feel suicidal at 10-20 km or less)