This one is rather odd, for me. My computer should be able to handle this game fine, even on all of the high settings and high textures. And it does; most of the time it's at least 40FPS on such settings.
...except when I get close to capital ships. This is where things get odd--how much my FPS drops depends on how much of any given capital ship fills my screen. This means that, unless I'm close to one, I can still get 100+ FPS looking at a max-res/setting Lucifer.
It's worst when I try to enter the fighter bays of any given ship. It gets so bad that I'm looking at single-digit FPS usually, sometimes as bad as 4 FPS. It can get about that bad when I'm right up against a capship, almost to the point of scraping against it, but it's not as consistent then.
So I figured there was some particular feature enabled that was just not meshing well with my system, so I turned off specular, glowmaps, and mipmapping. I went back in, and though things were slightly better, it was still largely the same--instead of completely crippling the gameplay at times, it was just an extreme inconvenience and something to avoid whenever possible.
As for more specifics:
1) Approaching a Sathanas' beam cannon, even when it fills 90% of my screen, doesn't affect my performance much (at least on the lower settings, that's all I've tried it on since the fourth or so mission).
2) It's worst inside the fighter bays, where even minimal textures, no specular/glowmapping/mipmapping, and not having much to see period (like when entering the Orestes' fighter bay, which is comparatively small and simple) still kills my framerate.
3) Framerate drops are largely minimal/negligible (or at least not a problem) until I get up close, where it quickly and suddenly plummets. Even when it only fills less than half of my screen, so long as I'm CLOSE to a capship, the amount that fills my screen seems to be much worse.
4) Certain ships seem to not affect my FPS nearly as much as others; a Sathanas is, in general, much less problematic than the Temarare. It can still get bad, but usually only when I'm very close to the main body of the Sathanas, looking right at it. However, ships that (I think) are still original to FS2, like the Demon destroyers or Lilith, still cause FPS problems just as bad as ones original to Blue Planet, under the same circumstances.
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There's actually another, small problem that I'm curious about: I can't map/bind any of my mouse's thumb buttons. I can map the "Button 3" (clicking the scroll wheel down), but that's it. Strangely, there's a "Button 4" and "Button 5" premapped in the defaults, but I can't remap them and clicking them when trying to create a new bind does absolutely nothing. It's not critical, but having two very easy-access and well-positioned buttons that I can't do anything with is kind of annoying, especially when there's a million controls to this game.
As an aside note, a lore/story/setting question: the Sathanas' beam cannons seem WAAAAY more powerful than they are in FS2--a single cannon destroys a full-health Orestes in under ten seconds (potentially under 7 seconds, if it doesn't stop to recharge). The Colossus could actually go toe to toe with a Sathanas when even two of its main beam cannons were operational. So, uh, is this a story-driven thing (as in, the mission is designed/coded for you to take out all of the four cannons before they could fire, so failing that is just coded/designed to be a nonstandard game over?), or is it that the Orestes/Raynor class is actually MUCH less durable than the Colossus, even beyond a mere size difference?
Oh, and did the Temarare defect, or not? Two of the database entries seem to contradict each other in that regard. And given the ship's and that ship's command staff's interaction with the Sanctuary, I'm shocked that there are indications that it didn't--given what the 14th just went through, I'm shocked that all but a few actually wanted to carry out orders to launch a premeditated invasion of a peaceful, united, and friendly Sol, from both a military, ethical, political, and diplomatic standpoint...