This paper proposes a high-speed and areaefficient three-parallel Reed-Solomon (RS) decoder using the simplified degree computationless modified Euclid (S-DCME) algorithm for the key equation solver (KES) block. To achieve a high throughput rate, the inner signals, such as the syndrome, error locator and error value polynomials, are computed in parallel. In addition, the key equations are solved by using the S-DCME algorithm to reduce the hardware complexity. To handle the many problems caused by applying the S-DCME algorithm to the KES block, we modify the architectures of some of the blocks in the threeparallel RS decoder. The proposed RS architecture can reduce the hardware complexity by about 80% with respect to the KES block. In addition, the proposed RS architecture has an approximately 25% shorter latency than the conventional parallel RS architectures.