MSI does not build sound cards or sound chips, they build motherboards.
MSI 845 Ultra = (MS-6398) w/Intel 845D chipset
MSI 845 Ultra Specifications:
Supports Intel. Pentium. 4 processor in 478 pin package.
Supports 1.5GHz, 1.6GHz, 1.7GHz, 1.8GHz, 1.9GHz, 2GHz, 2.1GHz, 2.2GHz and up.
/ PCI-6ch supports 2/4/6 ch speaker.
Intel. 845 chipset (593 FC-BGA)
Drivers are posted on the manufacturers website (as well as the Realtek website):