"The UAA-20K1 dual-chip (CA0112 “Golden Gate” chip) solution is similar in spirit to Hybrid VGA and 3D Graphics solutions. In the power-on condition, the dual-chip solution is in UAA mode as default. Upon Creative Driver startup or initialization, the software driver will switch the dual-chip solution to X-Fi mode. Upon Creative Driver shutdown or uninstall, the Driver will switch the dual-chip back to UAA mode. The switch from UAA mode to 20K1 mode, and vice-versa, does not result in a change to PCI configuration, as the OS would see it."
More here:
OEM - Chips - CA0112
and here:
OEM - Sound Cards - SB077x Family