It's a shame that the only response you received until now is from someone who doesn't have a clue what he's yammering on about half the time (not to mention it's horribly obvious he's never laid a finger on a Striker Extreme.
I have one in my main computer and I've used the onboard sound as well as the X-Fi Fata1ity.
The sound quality on the Supreme FX is HD and surprisingly good. It has one key feature for gamers that the X-Fi doesn't, that being support for that funky microphone with noise cancelling features and the ability to smoothly transmit voice while playing back the audio in a game, maintaining remarkable fluidity and clarity.
For I don't know how long now codecs have come with their own audio mixers and stuff, along with other interesting toys. Back when Flinstone there was actually using computers they may not have...but that was when their idea of overclocking was pedalling faster. The guy's knowledge on computers (apart from his cut and paste Google fetish) is so archaic his "computer tech" course was done with etch-a-sketches because noone could afford one.
The difference between an X-Fi and the Supreme FX, in most things, and especially with lower end speakers, is not really that noticeable. It's there, but barely.
Incidentally, EAX 2.0 and below can be found on many soundcards besides Creatives. And, of course, Direct Sound support was removed from Vista. Creative uses an OpenAL wrapper, as does other manufacturers. The Supreme FX actually uses OpenAL as well as opposed to Direct Sound.
The only genuine advantage to the X-Fi is for multi-track recordings.
