A b s t r a c t . In parallel processing, fine-grain parallel processing is quite effective solution for latency problem caused by remote memory accesses and remote procedure calls. We have proposed a processor architecture, called Datarol-II, that promotes efficient fine-grain multi-thread execution by performing fast context switching among fine-grain concurrent processes. We are now building a prototype multi-media machine KUMP/D (Kyushu University Multi-media Processor on Datarol-II) on the basis of the fine-grain multi-threading architecture. In the design of the KUMP/D, we used the commercial microprocessor for its processing element, and designed a co-processor, called FMP(Fine-grain Message Processor), for fine-grain message handling and communication control. In this paper, we show the KUMP/D processor design and its performance evaluation. * Currently, he is at NTT Software Laboratories.