The authors investigate a network emulator performance versus the variability of hardware/software features of the hosting machine. In particular, the evaluation of static and dynamic delays is carried out considering several testing conditions. In detail, as concerns emulator configurations, the influence of packet rates on imposed delays values and distributions are analyzed; as for hardware and software, different values for RAM, CPU cores and operating system are tested. Results, reported as mean values and standard deviation, show two main trends: the resource availability has an important impact on the emulation stability and on the measurement repeatability; secondly, higher differences in performance levels for low imposed delay values, which is the most interesting zone in a few milliseconds latency world. The paper aims to show that the capability to emulate network impairments is generally influenced by hardware/software capabilities and it must be considered when using network emulation for specific test purposes.