Update: The problem is really GTX 780. Everything works fine on Intel HD4600.
Has anyone using the latest Haswell platform booted the LiveCD successfully? I've tried Ubuntu and Ubuntu Gnome. They are written to my USB stick using the universal USB installer. I can see the boot menu, but when I select Try Ubuntu, the screen just goes black. I don't think it's reading the stick either, but I still waited for quite a few minutes.
I've installed Ubuntu several times since 8.04, and this is the first time I had such an issue. Is it because Ubuntu 13.04 came earlier than Z87, so the platform is not well tested? Has anyone successfully installed Ubuntu on Z87?
PS: I've already disabled those Windows 8 crap in UEFI (like quick boot, secure boot). My Windows 8 is installed in UEFI mode, and I believe I need to go through the UEFI hassle when installing Ubuntu as well. But I want to at least get into the LiveCD first just to make sure everything could work...