Windows 8 drivers for hardware that uses VIA's audio, networking, graphics, and card reader chipsets are available from their standard driver download page which I've linked to below.
VIA has both 32-bit and 64-bit Windows 8 drivers for the majority of their chipsets but according their Windows 8 driver FAQ here, the following audio chipsets should be supported by native Windows 8 drivers and will not receive further updates: VT1708, VT1708A, VT1612A, VT1613, VT1616/B, VT1617/A, VT1618, VT82C686A/B, VT8231, VT8233/AC, VT8235 & VT8237/R, and VT8251.
Note: These Windows 8 drivers are directly from VIA, a chipset manufacturer. A VIA chipset may be a part of your computer's motherboard or other hardware but VIA did not manufacture the device as a whole, just the chipset. Because of that, it's possible that your actual computer or device manufacturer has a better Windows 8 driver for your VIA-based device than VIA does.
