Ok, so my copy of MM9 is totally unplayable for me, because the mouse behaves as if it's drunk.

It jitters, doesn't read the inputs right. No idea if that's how the game works, as in: it's just busted like this. But I really don't want to put up with this.

I tried disabling Texture Optimisation (or something like that) in Video Options, and viola - the mouse does not jitter anymore and seems to read the inputs smoothly - but alas, when I go into any meny, there's a terrible FPS drop, including the mouse cursor, which makes the game even more unplayable.

I want to play this game. Please tell me there is a fix. I have MM9 from the Ubi store, if that matters.