Slight performance issues

[SpacedOut]

Hey guys,

Today I started noticing some performance issues playing diablo 3. At first it felt like some frames were just dropping, but it's a bit different. What happens is it feels as though the game is 'slowing down' for a second or two, then running faster for a second or two to catch up. This is most easily noticed in my character moving more slowly and controls being sluggish, then running quickly to catch up to where he would have been had the sluggish moment not happened.

It is not a case of connection issues, when that happens it manifests itself slightly differently as a skip, not a slow period. I have noticed that it most typically happens when a lot of physics are going on; for example when many destructible objects that fragment are being destroyed at once, or when a lot of stuff is going on. The really curious thing is the following however:

It only seems to have started happening in nightmare mode, and only when I'm playing with one or more other people. I played through normal mode mostly solo, with a friend at a couple of points and it ran perfectly smoothly all the way. When I play solo in nightmare mode, it also runs fine. When I'm grouped on nightmare mode, I get these little sluggish moments as I described above.

I'm playing on a laptop with a GTX460M Nvidia GPU and a i7 Q840 CPU. I've been running the game on max settings and have tried turning down the physics, particle and clutter settings with no real fixing effect with any of them.

One possible solution would just to be to run the game permanently on low graphics, which I would like to avoid since it runs perfectly most of the time and frankly should be able to run the game just fine. I was wondering if anyone had any suggestions or fixes that they found to a similar problem?

Thanks in advance.

PS: I ASSUME this is the correct forum to post this in, since it's diablo specific. Sorry if not.

[Deleted]

Simple answer, latency.

Edit; Nvm sorry for that. I've noticed only a few slowdowns if I'm joining a game where there's a proper spankfest going on, but it's generally over in 2 seconds.

[BicycleMafioso]

VSync on? If you press CTRL+R (default keybind) do you notice any drops?
If you have it in your nVidia drivers, have you tried disabling Vsync in game, and forced adaptive VSync through drivers?