1 - Simulink Real-Time is designed for Speedgoat hardware and does not support third-party target computers.
2 - Simulink Real-Time is the recommended solution when multicore and hardware acceleration on FPGA are required.
3 - Parallel Computing Toolbox is neither required nor used with SLDRT. The fact that 100% CPU utilization is reported by the operating system is the effect of the real-time kernel taking ownership of the CPU. It does not mean that the CPU utilization is really at 100%.