Problem with sound and performance

Hi guys!

Earlier today I got my new shiny LattePanda and so far I love it! But....
Even though I have the volume all the way up, the sound still is pretty low. I'm listening through my old Panasonic AK-55, which normally is pretty damn loud, but not with the LP. I have to turn the volume at max in order to hear normally.
Also the sound quality is awful. Way too much bass, while you can barely hear the mid and hi ends.

So I've searched Intel's website for a driver update, but found nothing. Infact, the sound card is not even listed there...

Also, there's a performance problem. Sometimes it kinda lags. For example - FireFox stopps responding for like 50-60 seconds, it takes some time to bring the context menus.. Stuff like this...

Is this a normal behavior for the LP and if not - how do I fix those issues?

The cooling doesn't seem to make much of a difference... Right now there's two heatsinks and two fans that're cooling it.

I've read somewhere that some setting in the BIOS could fix the sound issue, but I've no idea how to enter the BIOS.
Also, is it possible to install an earlier Windows version (like 7)?

Thanks in advance!

EDIT: I have the 4/64GB LP
The power supply is 5V/2.4Ah