This paper addresses optimum nondiagonal and diagonal amplifying relay matrices for the amplify-and-forward (AF) wireless relay networks. Single-input multiple-output (SIMO) nondistributed and distributed relaying system strategies with the relay power constraint are applied, based on the signal-to-noise ratio (SNR) criterion. By adopting the optimum amplifying relay matrices derived, the SNRs at the destinations are analytically and numerically investigated in order to evaluate the proposed system. In particular, using the SNR values, it can be
predicted which scheme would yield a better system performance than the others.