Lag with NetPlay

Hi all,

First, many thanks to the autors of this great emulator !
I'm posting here just because I have a simply question about multi.

I have no problem with playing games in offline mode because all the setting in options, are ticked (in particular Dualcore enabled) and make the games playing with a constant 60 fps.
But, in online mode, it is lagging a bit because I follow the recommended steps to make NetPlay working.
And it's working but the fact that the emulator emulates the games with only one core make all the games playing slowly (laggy)...
It is a bit better in OpenGl mode but the FPS falls down to about 30 with it...

My PC hardware is more than enough (i7 960, GTX 560ti 2GO, 6GO RAM).

So my question is : because we are obliged to desactived the Dualcore (inter alia) to play NetPlay, we will never play the games as fast as offline mode with optimisations enabled (DualCore) ? Or, I missed something ?...

Sorry for my bad english I'm French.

Thanks to those who would answer me.
Ben