The clock speed that the CPU was at when running the test. Some of the K series and overclockable AMD CPUS have as much variability as the laptop CPUs because of differences in overclocking.
Also to add on to JonnyH's point. More core in some cases can actually be detrimental to Single Threaded heavy workloads. More cores = more transistors, more transistors in the same size package/with similar power and thermal limits can impact heat generation and available power. One reason 16+ core server\workstation CPUs are not generally recomended for gaming or emulation, even when they have higher TDP and physical size. In laptops using the iGPU also can dump extra heat In the CPU package and decrease max frequencies, though if your discrete GPU solution is overloading the heat dissipation capabilities of laptop's cooling solution then that can be just as bad (*cough macbook *cough)..
Also to add on to JonnyH's point. More core in some cases can actually be detrimental to Single Threaded heavy workloads. More cores = more transistors, more transistors in the same size package/with similar power and thermal limits can impact heat generation and available power. One reason 16+ core server\workstation CPUs are not generally recomended for gaming or emulation, even when they have higher TDP and physical size. In laptops using the iGPU also can dump extra heat In the CPU package and decrease max frequencies, though if your discrete GPU solution is overloading the heat dissipation capabilities of laptop's cooling solution then that can be just as bad (*cough macbook *cough)..