Circa 2005, I bought a Dell XPS 600 2GB XPS with the Creative Labs X-Fi Xtreammusic and the 5.1 speakers runing XP 32 bit Pro OS. Needed to upgrade mem for my multimedia program, but XP is limit is 2GB.  Ran Windows 7 Upgrade Advisor and it stated the XPS 600 could be upgrade to Win 7 64 bits (allows lots more memory access). Advisor program noted that a new driver was needed for the X-Fi and gave a link to CL web page. So, I upgraded to Win 7 64 bit (custom) and all worked except scratchy sound. Followed link to CL SB and downloaded Win 7 64 bit driver. Did not work. After a week of trying and emailing to CL techs, they said that my sound card was a OEM card and that I had to contact Dell for the new drivers.  Dell web pages had no Wind 7 drivers and finally working with a Dell tech,  I was given a polite"brush off" and a driver link.  Installed driver from that link and same problem, sound would skip, was scratchy and squeelee.

I noted that there was an integrated audio capability on the mother board. Found a tight fitting cover over the plug ins in the back of the computer and removed it. After a few attempts to run the speakers via those plug ins, I realized the Realtek drivers were not installed. So pulled the CL SB card and downloaded the Realtek XP 64 bit driver from Dell. Rebooted and darn, it works.

Creative labs told me that OEM cards, Dell in this case, may modify the installation of their cards and that is why their Win 7 64 bit driver (beta when I downloaded it) would not work. So I needed to contact Dell to get the new driver.  Apparently Dell was not very interested in investing in supporting these old cards.

The sound via the Realtek is really good and on first blush, as good as the SB card.  So I will not be buying another commerical card.