Are you absolutely sure that your on-board audio is turned off in bios?
How about un-installing the on-board drivers? Maybe they're doing something funky in the background that the Xonar doesn't like.
Have you tried resetting the resource allocation in bios? Could be the on-board is assigned an IRQ that the Xonar needs and it hasn't been released by the on-board even when the on-board is disabled.
Could be any # of things, so perhaps if you listed what you have already tried we can spot something you missed.
It is also possible that the Xonar drivers use an undocumented hardware feature of intel chips which isn't included in AMD chips, but it's been a long time since I saw something like that.... (trying to rip mp3s with my K6 took almost an hour per song while using a similar intel chip was only 5 minutes).
__________________ EVGA X58 3X SLI / i7 980X / 3X 4G Mushkin Blackline Frostbite / XFX Pro 1000W / EVGA GTX 680 SC+ 2GB / Corsair F120 / WD 6401AALS / TT Lvl 10 GT Swiftech MCP655 WC Pump / EK XT 240 Rad / 2X Scythe Ultra Kaze / EK Supreme HF / Primochill Myriad Dual Bay Res / Dell UltraSharp U2412M Sabertooth 990FX / PhII X4 965 / 2X4G Corsair XMS3 / EVGA GTX580 + EK Block / Corsair 120G Force GT Corsair TX750 / XSPC EX240 / Swiftech MCP655-B / XSPC Dual Bay Res / ? CPU block / Bitfenix Ghost / Samsung 931BF |