The precision mode in 1.0.8.2 brings significant sound quality improvement - broader soundstage and noticeably more details. According to Musiland's website, previous drivers use two separate DCMs within the APU to generate clocks for 44.1kHz and 48kHz, while the new precision mode combines the two to generate one clock for a given sample rate, and this gives lower gitter and better sounds. However, it also means changing from 44.1kHz to 48 kHz takes longer (2-3 seconds) since the FPGA needs to be reprogramme on the fly.
BTW I'm using Windows 7 64bit, no problem with the driver. You need to uninstall the old driver, restart, and install the new driver.