RISC-V is a new instruction set architecture (ISA) that has emerged in recent years. Compared with previous computer instruction architectures, RISC-V has outstanding features such as simple instructions, modular instruction set and supporting agile development. Due to these advantages, a large number of chips have been designed based on RISC-V ISA. However, compared with other ISAs, the efficiency or performance of RISC-V architecture is still not clear. In this paper, we investigate the performance difference of three mainstream RISC processor systems (i.e., ARM, MIPS and RISC-V). We use two open source benchmark tools-UnixBench and LMbench, to widely evaluate the processor performance, such as computing efficiency, read and write file delay, local communication bandwidth, etc. A total of 19 detailed performance tests on these three ISA systems are carried out. The testing results show: i) MIPS achieves the highest scores and shortest context switching delay whether it has a large number of file copying or pipeline communication; ii) RISC-V has high local communication bandwidth and strong scientific computing capabilities, but has highest communication and file access delays; iii) ARM’s local communication bandwidth is low, and the delay in all aspects is slightly higher than that of MIPS.