Checking the board's manufacturer's support site for "4 in 1" updates availble for that mb
would provide an updated sound driver for the onboard. Newer games like Q4, Doom3, and
others like Battlefield 2 and HALF LIFE 2 place high demands on system resources. Most of
these games also expect the latest updates installed for newer model video + sound cards.
Updating with the latest video drivers can sometimes help there too.
With a new system on the way an investment in a new sound card not quite want you are
wanting for a new custom build would be a waste of time and effort. See if updates can be
downloaded for your present hardwares. That could be a help there.