It has been ages since this original post and still this thread will pop up on Google's results when searching for X-Fi related topics.
I have learned a great deal about the X-Fi's in the last several years. I mean, I purchased my XtremeMusic in 2006! It's 2015 now and I'm 100% convinced this card was the single best purchase I've made in my entire life! Creative even claims it'll continue to support it with updated drivers for the upcoming Windows 10 OS!
Now, back to the topic, it is actually possible to get anything from 48KHz to 192KHz into the sound card without much of an effort. Note that 192KHz is only supported in stereo mode. On Windows, it's as simple as choosing the corresponding sample rate on the Audio section in Control Panel and you're off to go. Now, you can't expect exact bit-perfect audio in Entertainment or Game mode as the X-Fi chip will always do some (near lossless) upsampling in those operating modes. You can check
this web page for more info on the X-Fi's SRC. The thing is, I've run extensive and thorough tests and I can guarantee that the X-Fi at least never downsample anything so you'd lose audio quality. The most it'll do in Entertainment or Game mode is
upsample audio and, as it is super efficient at that, you can't possibly hear any distortion whatsoever.
If you really want bit-perfect audio, which doesn't make much of a point to me unless in very specific situations (like audio playback capturing using WASAPI or WhatUHear – I use that to clone Spotify songs... haha), you can always use Creation Mode and manually set sample rate to whatever value you also set the Windows Audio Control Panel (let's call it WACP from now on). Or you can use ASIO and have sample rate switched automatically for you.
I've tested ASIO in Entertainment and Game mode as well. It does seem to switch the cards master sample clock according to whatever your source audio is, but still the card will do some upsampling, so no bit-perfect audio unless in Creation mode.
OpenAL bypasses the software-based Windows mixer. It makes Windows Vista / 7 / 8 / 10 work just like Windows XP. It'll make the sound card do all the mixing and resampling in hardware instead of having Windows mixer do it for you.
You can have Windows Media Player or
Foobar2000 use ASIO. With
Foobar2000, you can also use OpenAL. The advantage is you can leave WACP set to, let's say 48KHz/24bit all the time and never worry about sample rate switching again as ASIO and OpenAL still use hardware acceleration and will have the card do everything for you at the highest possible quality. If you use the standard Windows sound system instead, that is whenever you're not specifically using either ASIO or OpenAL, then you have to keep changing sample rate in WACP manually all the time if you expect Windows mixer not to do any resampling on its own before sending the audio to the sound card.
Note: the
current X-Fi driver for Windows 8 / 8.1 (SBXF_PCDRV_L11_2_30_0004.exe, released in March of 2014) has a bug in which, if you choose 44.1KHz audio in WACP, the sound will be heavily distorted. The workaround is play any 44.1KHz audio with Foobar2000 using ASIO as it will set the sound card master sample clock to a matching multiple of 44.1KHz instead of the standard 48KHz. If you do that with foobar, you can use 44.1KHz in WACP with no distortion whatsoever. Whenever you reboot your PC though, you have to do the thing with Foobar again to get rid of the distortion.
I keep on doing that, it has become religious already: do I want WACP set to 44.1KHz? Then I open a 44.1KHz file with Foobar2000 outputting sound through ASIO. Do I want to switch back to 48KHz in WACP? Then I open a 48KHz file with Foobar to get the sound card back to the standard master clock. Thus, I get no distortions in the current buggy driver.
If anyone needs help or wants to talk about the X-Fi cards, I'm very open for that. Just send me an e-mail to
medeirosdez@yahoo.com.br with a clear X-Fi related subject and I'll be more than happy to set up a virtual meeting, like Skyping or using Google Hangouts or whatever.