This paper presents a clustering method called clustering design space exploration (CDS-ExpA) to accelerate the architectural exploration of behavioral descriptions in C and SystemC. The trade-offs between faster exploration versus optimality of results are investigated. Two variations of CDS-ExpA were developed: CDS-ExpA(min) and CDS-ExpA(max). CDS-ExpA(min) builds the smallest possible clusters while CDS-ExpA(max) builds the largest possible ones, reducing further the design space. Results show that CDS-ExpA(min) and CDS-ExpA(max) explore the design space 90% and 92% faster on average than a previously developed annealer-based exploration, method, at the expense of not finding 36% and 47% of the Pareto optimal designs and finding the smallest design that is 7% and 9% on average, larger, and the fastest design 28% and 32% slower, respectively.