I have had pretty great performance with this game in MP for a while now. I have helped fix others performance issues as well and figured I would share some of the things I've done to help with your own performance woes.
First things first, don't use any automatic settings. Most of them are bugged and make the game look like complete crap and some even negatively impact performance. Everything needs to be set manually for best results. I mean EVERYTHING.
1. The biggest contributor to my FPS drops was the shadows. Turning them off gave me an extra 10-20FPS and reduced my FPS drops dramatically. So be sure to disable those completely, it helps a massive amount.
2. Next make sure Ambient occlusion is also disabled. It has an absurd impact on performance for the small amout of visual fidelity it adds to the game.
3. Textures should be set to normal for best performance and minimal texture tearing issues. Some may be able to get away with high, but your texture issues will be more frequent and your results may not mirror my own. This will help a lot with FPS drops and stutter as well.
4. Next you need to put Anisotropic filtering in-game down to low. Once that's done force your preferred amount of AF through your GPU control center. This helps with general performance and once again FPS drops and stutter.
5. Run in borderless windowed mode. This helps with mouse lag and FPS stutter.
6. Don't use any in-game overlays such as FRAPS, Steam overlay, etc. These help produce mouse lag and FPS sutter when they are active. After the recent patch the Steam overlay doesn't seem to be much of an offender if at all, so something to keep in mind.
7. Keep motion blur, depth of field, and distortion off. These all have some negative impact on your performance.
8. Terrain detail should also be off, visually I can't pinpoint what it adds and it can have some massive hit on your performance. Keeping this off will help maximize your FPS and reduce drops/stutter in-game.
Be sure to completely restart the game after applying these settings.
Well that's all I got guys, I hope these changes help your performance as much as they have helped some Steam friends as well as myself!
People with decent rigs that have those problems shouldn't have to do that?
It's not a question of if you should have to do it or not. When and if the games issues get ironed out then you won't have to do it anymore. But until then, why not try and maximize your performance and along with it improve your MP experience?
Decent rigs to high-end rigs like mine...let's face facts people...the game is not optimized and until then, the steps mentioned above will improve performance dramatically. I tried forcing the settings all decked out and that's not going to happen on a game that isn't playable with them. We all know how frustrating it is to be waiting for the main issues to be fixed, but until then...do what needs to be done to at least enjoy the game for now. Yes, IW is taking forever, yes this is crap it was launched like this...but either stop playing the game or deal with the issues that are present.
Oh I 'can' get rid of most of the FPS Drops if I want Console rendering and you're still stuck to P2P from some Dude's K-Mart ISP Laggy Lobby, but if I have to stoop to those crappy rendering levels then I might as well toss out my i7-3930K, 32GB RAM, SLI GTX 770's and go buy myself a POS XBone or POS4.
However, even if I render crap then I'd still have to tolerate Hacked & Infested lobbies.
The game is DOA and at this point IMHO IW just needs to drop PC support. IF I could get on a decent Admin (Kick + Ban) Ranked Private Dedicated Server ... then please let me know and send me a PM and I'll be there!