Update:I forgot to mention the strangeness of how the game seems to try to update the terrain when flying. Specifically:
(1) There seems to be a transition when one lifts up far enough above the ground that small details start to become obscured. By "transition" I mean that the game will even stall out (frozen, burning fuel, as the game loads/caches terrain data) when merely moving vertically. Could this be the game loading additional terrain data because the higher altitude allows seeing the distance further?
(2)The game will stall even when there is nothing but ocean below - no visible land. This seems like such a waste of CPU cycles and disk activity, to load or calculate something which is not even visible to the player! What is the game doing - calculating massive cavern systems below the oceans? It should not even bother to calculate the ocean floor unless it is visible from the player's viewpoint several hundred meters above.
(3) Watching how the game slowly draws the landscape, I noticed that the first thing it does is display
WATER underneath every square of terrain... But,
why? What's the point? Again, this is something that players will never see unless they are flying over an ocean. There should not be an ocean of water under the land, anyway.
(4) With Voxel Cache left on, it does not seem to help flying over explored terrain. But - for me, anyway - turning it off did not seem to improve or worsen performance, either. (See the
Voxel Cache / drive error Steam discussion for details.) Flying back over terrain which I've already explored does not seem to be any faster than exploring new terrain. Indeed, it almost seems like the game is trying to update old explored terrain, leading to the same stalling and lack of performance as flying over new, virgin terrain.
(4.a) As evidence of my theory (updating old terrain instead of properly using it as cache to speed things up), I've noticed that the game will pause/stall to update terrain even over explored terrain when said terrain
is still visible below. It does not look like it needs to be loaded from disk or recalculated, but it stalls anyway. And then, right before the game resumes and I can fly again,
I noticed that the terrain visibly changes, but ever so slightly. The fact that it subtly changes implies that the game had to recalculate or reload something already there.
(4.b) Further evidence that the game is
not properly utilizing the Voxel Cache (when on) to speed things up is how it
forgets explored terrain. When flying over already explored terrain, I get stalled and I watch as it slowly redraws
most of it, as if it is unexplored terrain. Strangely, though, this is patchy. Parts of explored terrain remain behind, while other parts just disappear and have to be reloaded or recalculated.