another solution would be to buy a Z series audio card from creative.
problem is xfi cards, is they are getting old. and so is the support.
the software that runs the drivers for the xfi has not been updated in almost 4 years. even back then drivers where flaky
I ended up getting a ZxR card and no problems with mic. and drivers give me no problems
Any of the Creative PCI Express sound cards with a DSP end-runs a known hardware issue with the PCI sound cards (specifically, the X-Fi cards) unrelated to the issue you're having.
The issue is an address bug at the 4 GB area (therefore, it only affects PAE-equipped or x64 operating systems AND if you have 4GB or more of system RAM) - it was a minor nuisance with XP; however, it's a decidedly bigger issue given the x64 boom since. The "bug" manifests in Windows 7 or later as a BSOD (WHEA_UNRECOVERABLE_ERROR).
While the Z is the latest/greatest PCI Express sound card, the earlier PCI Express sound cards (Recon3D, TitaniumHD, etc) use the same SoundCore DSP that the Z does - the difference is that the Z series has newer DACs and supporting electronics.
That particular issue is, in fact, the ONLY issue I had with my low-profile XtremeGamer - however, that was ALSO the reason I retired it (replaced by a refurbished Recon3D Fatality) and did NOT pass it to my Mom (which is atypical) - she has more system RAM than I do.
Curiousity factor - I have to wonder if the Recon3D could, in fact, use the same software that the Z does (remember, the same was largely true of the Audigy and X-Fi, despite the DSP differences - the Recon3D and Z don't differ even there).