I can open 3 games now and working good

But I can't open 4 games. I open games at the ISBOXER by select Character Set . Sometime the NO4 game can open up,but not always. Can someone help me?
And Can ISBOXER use follow map-key?

[Alge]

It may be that your PC is not capable of running 4 instances of D3. The HOWTO:Tweak your framerate wiki page covers most of the things you can do to try and improve things. Section 5 on Identifying framerate bottlenecks may be particularly applicable here.

I can open 4 game before using ISBOXER and run good.

[Alge]

Everything in that link still applies.