Q: I want to get the best performance out of my Z-5500's http://www.newegg.com/Product/Product.aspx?Item=N82E16829127002 http://www.newegg.com/Product/Product.aspx?Item=N82E16829156006 http://www.newegg.com/Product/Product.aspx?Item=N82E16829271001
A: Best performance for what purpose? I'd expect all 3 cards you list to be roughly equivalent, assuming the companies didn't mess up the drivers. The cheaper 2 both have the CMI8770, while the most expensive has the CMI8788, but the only listed advantage for the 8788 is the 192kHz sample rate, which is more than your speakers can do, anyway. The most dramatic differences are usually in the amplifier support components, but the Z-5500 has digital inputs, so the difference becomes driver support. In many cases, you could use drivers from one card on another card, if it has the same chips. However, due to patents and Creative's evil handling of the legal system, the best performance you can get in games is from Creative's X-Fi sound cards, that support the latest EAX protocols.