Ive also got issues with my Prelude. I have tried every driver for it under the sun to no avail.
My issue is that my MIC is either crackly or makes my voice stutter. This happens when using a comms program like TS or steam and is annoying. I can however fix this by changing the mic sample rate but this is only a temp fix as it will happen again.
I also have another issue, well had. Sound just randomly stops being outputted through the card. Whether it be through optical on my Z-5500's or through the standard connectors.
I have a mate who is using a prelude and says its completely Faultless. He has a 680i board. He got his not a few months ago. I got mine about 6-8 months ago.
I have just contacted the shop I got it from and they have given me an RMA number as I explained the issue. I will be returning it for replacement on the 5th Jan.
noname, if you get on msn or something, I can send you the drivers I have been using for ages which are no longer on Auzen's website.
My guess leads to a possibly faulty component in a certain batch of cards. However, I will have to wait for my replacement until I can confirm this.