@freediver - in addition to the many comments above regarding purity of conductors and different material types - I believe a couple of other factors in cable performance is the "geometry" and "size" of the conductors
Geometry: is how the conductors are placed withing the actual "cable" itself e,g, one of the most well known geometries is braided - as in Kimber Kables.
Size: of late there is now a growing trend to use a different gauge conductors for signal and neutral conductors.
Personally, after a lot of trial (and error) experimentation - I now use a "helix" cable, where the neutral is twice the gauge of signal conductor and is wrapped around the signal conductor. See link below
http://image99.net/blog/files/d048bbacfce9bcad4a025be804771d9a-76.htmlMy thought process is that this design eliminates any noise transfer (by inductance) from the signal conductor into the neutral conductor, which can occur with cables where the two conductors lie side-by-side inside a sleeve.
The noise transferred into the neutral is fed back into the neutral side of the amp and interferes with its operation , so removing that noise enhances clarity. Enhanced clarity also improves the "phase effect" between left and right channels which improves the Imaging.
I’ve found the Helix design provides exceptional clarity and superb 3D imaging along with a more detailed and deeper bass performance.
My thought process may be "flawed", but the Helix Cables works exceptionally well :-)
Anyhow - I believe geometry is just one more thing to consider when selecting ALL cables.
Regards - Steve