Can you explain what do you mean by "slow" regarding grub?
Regarding your Intel HDA, i have booted into live mode in PCloS & SImplyMepis and sound didn't work. I messed with alsamixer but to no avail. Then booted with Mint 8(GNOME) and yet no sound initially. I opened Pulseaudio configuration and under one tab selected "No Amplifier" and voila, sound worked

I still can't understand what that option is in alsamixer.
Sabayon maybe a loaded distro but a little complex to administer for new users.
Mint KDE4 CE is very good.