From what I take from your post, you feel as though Ketx's drivers do nothing but change the display name.
I don't "feel" that's all Ket's drivers do. I
know that's all his drivers do. If you doubt... download the reference 2.21 drivers from RealTek and do a binary diff between the Realtek installation package and Ket's package. The only differences you'll find is in the INF files, where names have been changed "HD" and "High Definition Audio" replaced with "X-Fi"
blindly (hence an entry of an "X-FiMI" device.). Diff tool I used: Windiff (available with certain versions of Microsoft Visual Studio).
On Vista this does absolutely nothing other than rename the device. Using my previous analogy, Touareg/Cayenne... simply changing the name doesn't change how it performs. Under the name it's still going to be a Touareg.
However: I'm
NOT saying that adding the X-Fi MB software over the top of these drivers on
XP do nothing. On Vista... they do nothing, since they won't find the device (since the device GUID hasn't changed remember, neither has the registered binaries). Since
my interest is for Vista/Win7, I'm not interested in how or if things work on XP.
However, from my own RMAA tests, I have see improvements between stock and Ketx's drivers. I can't perceive any difference, but RMAA says there is a difference.
You
have set up your device in BOTH instances to disable all effects and have the mixer set to exactly the same settings with both Ket's and RealTek reference drivers, WITHOUT having the X-Fi MB software installed right? And you have run the RMAA series of tests multiple times right? (A sample size of "one" is not statistically useful).
If you're running your RMAA tests on an XP system with the X-Fi MB software installed, you're skewing the results since the X-Fi software will be tweaking the audio before it gets rendered. Apples/Apples comparison and all that...
Question: how much of an improvement does RMAA report? If the change is less than 1% then it is not of interest since you'll never hear that minor amount of change. (unless you're an audiophile in which case: why are you not using a better soundcard to begin with)
This whole matter has become confusing and I don't really know what to believe anymore. I wouldn't put it past creative to spread FUD (fear uncertainty and doubt) amongst us here as modifying their drivers has not exactly gone over well in the past.
In this particular case I don't see the point for Creative to be spreading FUD... since Creative's drivers are not the ones being modded, Realtek's drivers are.
In the end, do your own analysis and draw your own conclusion. I've presented my own conclusion and reasoning, you're entitled to yours.