Just got a Cosmos II 15'6 yesturday, I love it a very well build laptop by my standards anyway.
But i just have this one problem, like the title says the sound is not automatically switching between the headphones and speakers.
I'm using windows 8
If you have set the speakers as the default device, then plugging in headphones will not automatically switch to them. Set them as default and try agian.
I found that the audio was better without the audio drivers installed, the audio drivers seemed to cause stuttering in the sound. Uninstall the audio drivers and try. Also, you need to set your headphones as the default device under the control panel.