I have found USB audio streaming with Windows 7 64-bit to be extremely hit or miss. I have it installed on four systems: three desktops and a laptop.
The laptop is an Intel dual core Dell Latitude that shipped with Vista Business 64 bit. When using high-quality audiophile-grade outboard USB DACs, I would get popping and skipping from the get go. Upgrading to Windows 7 did not resolve the issue. I tried
disabling various drivers, updating them, disabling devices, monkeying with wifi settings, etc. No go. It happens irrespective of running various Windows 7 troubleshooters or trying the stock Microsoft suggested fixes. DPC latency spikes abound.
On an AMD box I built myself for work (Phenom II 965 BE quad core with 8gb of DDR3 on an Asus mobo, using high quality Seasonic power supply and other high quality components), I have no trouble using an outboard USB DAC for audio. No skips, no spikes,
etc.
On a Dell XPS 420 with 4 gb of DDR2 memory, I can get audio from the OEM Creative sound card that is fine, but if I switch to an outboard USB DAC, I get random pops, pings, and skips all throughout the sound.
On an Intel 1366 (i7-930 6gb of DDR3) system that I built on an Asus mobo using high quality power supply and components, I get good sound from the onboard Realtek audio chips. However, if I switch to an outboard USB DAC, the latency problem appears and
I get terrible audio.
Again, with all of these machines, I've gone through the various processes of trying to hunt down culprits to no avail. It seems to be a Windows Vista/7 problem. I never had this problem with XP 32-bit on the three or four computers I used it on.
It's really frustrating because I have an excellent headphone amplifier and DAC that I use to listen to lossless rips of my music. Windows 7 has essentially ruined the experience of streaming computer audio for me.