Creative's dedicated sound cards still make a difference when PCs struggle to sustain 30FPSon certain games, (and can help getting a stable 60FPS) on poorly optimized titles (or games that have been plagued by Denuvo).
I suspect it mainly has to do with the fact that Windows usually outputs uncompressed audio (due to requiring extra licencing for codecs like Dolby on a general-purpose PC, unlike consoles).
Because of that, a dedicated sound card will take that weight off the CPU.
In my case in particular, i noticed an 5-8FPS increase when playing AC:Revelations with my dedicated sound card (bear in mind, my CPU is merely a Core 2 Duo), but that's because i still don't have the money to upgrade my whole rig.
Back on topic, i saw a video by Anton's Hardware that made a deep research on the topic, and while the conclusion was that, yes, on current games & hardware it didin't make up much of a difference, it could be useful for specific cases, (in some poorly optimized games you can get better frames, and in well-optimized games can push FPS a bit further.
To finally end my comment, i'll add a link to the video i just mentioned, along with one of the comments that i think demonstrates a "best case scenario" for the use of a sound card in current gaming.
I used to use sound cards myself ages ago for MIDI and DirectSound acceleration. I didn't expect the hardware audio codecs to actually make a difference.
Nothing is stopping me from installing a PCIe Sound Blaster with a good old EMU chip. At least I hope so, the EMU10k1 and 20k1 have a hardware DMA bug which breaks them on systems with more than 2GB of memory lol
Not sure if I should go the CMedia route and just use Xonar instead. I do like Creative's features (especially ALchemy), but those you can gain on any machine using a software suite made by Creative themselves.
I mean i don't remember having audio driver issues last time i used Ubuntu on my desktop PC (i think at the time i had an Audigy SE, now i have an X-Fi XtremeGamer).
You got me curious, i'll try it as soon as i can and i'll tell you back the results.