Originally Posted by jeffmd
But who is doing the rendering of the sound? Is the X-Fi rendering the sound and then passing it to the hdmi output?
What I am trying to get at here is that 3d sound in games is complex. The X-fi is more then just an upgrade for your on boards DAC, it actually has a dsp to offload the 3d sound modeling from the cpu. This can be a pretty heafty process in todays games. If you are simply telling windows to use your video card as a sound source then I fear all the sound modeling is being done on the cpu thus cutting into your performance.
There're fewer games using DirectSound3D with the EAX extensions. Newer games use XAudio (the Xbox 360 sound system on Windows).
While XAudio does use slightly more CPU and the 3D reverb isn't as nice, it sounds* the same on all hardware be it onboard or even an X-Fi and makes it easier to port 360 games/develop cross platform as the audio API is exactly the same. The Windows X-Audio system will encode game audio into surround even on the ****tiest onboard audio solution. It also makes the user experience consistent for all users irrespective of sound card manufacturer.
There're fewer and fewer games which use DirectSound3D or OpenAL. Creative effectively killed their market by being the only hardware 3D vendor on the market and charging premium prices for their hardware.
I have two X-fi cards gathering dust, a PCI X-fi Extreme Music from 2005 and a brand spanking new X-Fi Fatality Titanium Pro. Both have serious issues on Windows 7 (I have 8 GB of RAM and Creative's drivers have issues on systems with more than 4 GB of RAM (even x86-64 based systems). Driver updates are few and far between and they're barely functional. I had the audio cut out on me during cutscenes with the X-Fi in Mass Effect 2. Onboard Realtek audio just works though they have no virtual headphone surround effects at all unlike the X-Fi.
*The positional audio and reverb effects are exactly the same on any card. Actually DAC quality will make things different.