Developments in recent electronics result in electronic components that produce heat, namely, Central Processing Units (CPUs). One solution to this problem is using a heat pipe. In this study, a cascade straight heat pipe (CSHP) is analyzed as a CPU cooling system with three effective lengths: 20 cm, 23 cm, and 26 cm. The first workload provided was Idle; the processor only ran the operating system without a software load, so that the processor utilization was only 1-10%. The second was full load, where the processor utilization was 95-100%. The CSHP-based CPU-cooling system with an effective length of 20 cm was able to reach processor temperatures of up to 43.32oC (idle) and 63.62oC (full load). For the effective length of 23 cm, processor temperatures of 46.99oC idle) and 64.81oC full load was attained. Lastly, while using the effective length of 26 cm, processor temperatures of 50.67oC idle and 65.21oC full load were reached. CPU cooling systems using CSHP are thermally resistant when in idle conditions; respectively, the temperatures for the effective lengths of 20 cm, 23 cm, and 26 cm are 0.168oC/W, 0.197oC/W, and 0.223oC/W. In contrast, for the same effective lengths, the thermal resistance at full load was 0.262oC/W, 0.236oC/W, and 0.224oC/W, respectively. Overall, the cascade heat pipe shows better cooling performance than a stock cooler.