I already have the Agent.exe ended and the DiabloIII.exe at High priority, and that helps a quite a bit, but it still takes me about 20-25 minutes for an alkaiser run with my Perma-Tempest Rush Monk.
The biggest problem I have is the random lag spikes that just straight out kill me, though I'm thinking that's the battle.net servers. The rest is just regular lag that sometimes won't let me pop a pot or Serenity in time.
I'm playing on the absolute lowest settings and I can run Skyrim on medium without lag.

I have the same problem, being in Australia doesn't help. I'm also in need of some advice in this area also. =)

How do you make the Agent.exe ended and the DiabloIII.exe at high priority? Can I do the same? Lag appears most for me when I log into the first new game, during the first few seconds of the first encounter with mobs.

Posted by douvinsky at 12/20/2012 04:41 AM

How do you make the Agent.exe ended and the DiabloIII.exe at high priority? Can I do the same? Lag appears most for me when I log into the first new game, during the first few seconds of the first encounter with mobs.

Same. My first battle is scary.

I still lag really big at the first encounter of a playthrough, I think that's just you computer processing a lot of new data all at once. I'm not sure if this will help with that, but maybe it will for you.

To turn off the Agent.exe and set the DiabloIII.exe priority to high (for Windows XP, I should also works for Windows 7 as well, since a friend of mine uses Windows 7 and he does this, too.)

1.) While the game is actually up, after you've logged in, Press Alt + Ctrl + Delete (the actual delete button under the insert key, not backspace). This will bring up the Task Manager for your computer.

2.) Find Agent.exe, right-click it, then press 'End Process'. Agent.exe is a updater for Diablo 3 and most of the time does nothing but check for updates, which uses up CPU, which leaves less for you computer to use for Diablo 3, which causes some lag. Ending it does nothing negative in my experience. Especially since most updates for the game take down the servers anyways.

3.) Find DiabloIII.exe and right-click it, then go to priority, then set it to High. Setting it to high means your computer devotes more resources to it before other things, which means that Diablo 3 will be receiving more CPU, and thus run smoother. I wouldn't recommend the Real Time option, even though it is higher up than High, I tend to stutter when I tried it.

On a side note, I would not recommend messing with anything else in the Task Manager. Most of the programs there are what make your computer actually run. If you do accidentally End Process on something else, just restarting your computer will fix it most of the time, since a restart will restart all background programs as well.

Hope this helps with some people that have lag problems like I do, or even people that want to get even more fps. ^^