A performance comparison between the electrical Cu-based backplane and a full-optical fiber-based backplane is presented in terms of capacity and power consumption. By means of systematic simulations we find the electrical configuration, which allows to optimize the Cu-based backplane by exploiting the best technologies available today. On the other hand, a fiber-based optical backplane is proposed by exploiting the most performing VCSEL sources. Limitations of the electrical and optical approaches are discussed, considering their capabilities to support up to about 25-Gb/s transmission and the possibility to evolve towards higher bit-rates.