I have Company Heroes on Steam. I can play the game on the Highest settings and highest detail and it does just fine, but when I got online with two friends it began lagging terribly, even when I turned the settings to their lowest quality graphics. Also, my internet connection isn't bad either.
I don't understand why it's doing this, my friends weren't having any trouble, except one of them couldn't load it right, but after we restarted he was fine.
I read here that disabling Prefetch is bad on Vista and 7: http://blog.tune-up.com/myth-buster/myth-busted-why-disabling-superfetch-on-vista-and-windows-7-is-a-bad-idea/
I'm using 8.1, so I don't know if that applies to me. Does running on windows 8 have anything to do with it, because I've heard of other's having online problems and I don't think they all were using Windows 8/8.1