There performance issues aren't limited to Logitech devices - I've had the frame rate to permanently drop to extremely low levels and I have never owned any Logitech peripherals.
In-game FSAA disables soft shadows. Nvidia control panel doesn't allow overriding program settings. I got AA working with the main game using Nvidia Inspector, but not with the expansions. The method used resulted in poor performance, the game was dropping below 60fps in the introduction sequence and runs far better in 4K (HUD is too small unfortunately) than in 1920 x 1080 with AA based on my testing. I did not enable supersampling unlike in the guide.
https://web.archive.org/web/20081210155127/http://www.projectorigincommunity.com/forum/archive/index.php/t-863.html / https://web.archive.org/web/20081018205848/http://lithfaq.com/forums/viewtopic.php?f=114&p=3167