Really? Referring to silver, Anne Marie Helmenstine, Ph.D. says:What do you guys think about silver coating? Silver does have a slightly higher conductivity and lower resistivity than copper (link). Some people use those figures in combination with silver's resistance to oxygenation (theoretically creating a longer-lasting cable) and the "skin effect" to justify silver-clad cables, silver solder, etc.
"Although it is the best conductor, copper and gold are used more often in electrical applications because copper is less expensive and gold has a much higher corrosion resistance. Because silver tarnishes, it is less desirable for high frequencies because the exterior surface becomes less conductive.