Reed-Solomon (RS) codes are among the most widely utilized error-correcting codes in modern communication and computer systems. Among the decoding algorithms of RS codes, the recently proposed Koetter-Vardy (KV) soft-decision decoding can achieve substantial coding gain, while has a polynomial complexity. One of the major steps of the KV decoding is the factorization. The root computation involved in each iteration level of the factorization is traditionally implemented by exhaustive search. A fast factorization architecture has been proposed to circumvent the exhaustive root search from the second iteration level by using a root-order prediction scheme. However, the root computation in the first iteration level is still carried out by exhaustive search, which accounts for a significant part of the overall factorization latency. In this paper, a novel iterative prediction scheme is proposed to compute the roots in the first iteration level. The proposed scheme can substantially red...