Two cable questions

Silver conducts 106%, if copper conducts 100%, and whether the current alternates or not, should have no bearing. I believe that there is less resistance at the surface of conductors, so the electrons are taking the path of least resistance, and hence the skin effect. It's more complex than all that, but I'm no theoretician. And just knowing the basics doesn't mean at all that you'll be able to predict which cables will work best in your system before you try them, either.

One thing to remember regarding the silver versus copper conductivity debate. Silver oxide is conductive, copper oxide is not. Thus, as these conductors age, the disparity between them becomes greater. Silver is best(AC or DC), followed closely by copper, then a fair sized dropoff to gold.

This is to quantify the conductivity differences of silver and copper. Silver: 62.9, Copper: 60.7, Gold, 48.8. So, silver is actually 3.62% more conductive. Source is MIT's website.

These are all excellent responses, but as Carl says, you cannot judge a cable by the specifications, whether you are discussing the metals, the insulation or the shield. Even micro changes in any one of these affect the final product. I have even tested soldering the connectors with three different types of solder, and gotten a substantial change in sound. Again, as stated over and over by MANY of the Audiogon posters, you need to try the cable in your own system, and not worry about who else likes it, or why it should or should not work.