For me there are three main issues regarding performance:
1) Heat vision. This is sometimes unplayable. For some reason the FPS can drop dramatically when enabling heat vision. I can not give a fully reproducible description, but at some point I guessed one particular case of this happening was in Frozen City, when entering fog areas. This is not the only case of the issue though, just the one, where I repeatedly saw it happening.
2) The game is obviously precalculating/initializing/loading material while progressing through a map (mechs, animations, special effects (shaders?), textures?). As I am not a developer I obviously can't tell what it is, but certainly on my computer it causes full-stalls of the FPS for some milliseconds. If that happens in a battle it's quite likely I am losing because of this. In other circumstances it still lowers the games appeal. I wouldn't mind, if I had to wait longer before a match or even before the game starts up. Just in games this is annoying.
3) The game stutters/stalls for noticable time, when moving the camera aburptly, e.g. by changing direction on a light mech at full speed or quickyl twisting the torso. This doesn't go away after that area has loaded, it seems just that the games performance is so low, that it can not handle this kind of fast paced gaming. It's one of the reasons why it's unattractive to me to play a light mech. I am aware, that a core 2 duo (wolfdale 8200)@2.66Ghz with an ATI 6850HD and 4GB RAM isn't a top end setup, but not absurdly terrible either.
Edit:
MWO is currently the only application on my computer managing to blue screen my Windows7 64 bit. I think MWO is crashing my ATI display driver obviously I have the most recent version installed). You guys probably need to sort out with ATI if there are issues in their driver or whether you are using a feature not supported in this particular way from ATI. The issue happens maybe every 100 games.
Edited by Autobot9000, 20 September 2013 - 09:30 AM.