Time synchronization performance of desktop computers

Time synchronization is a vital requirement for various applications. Especially the synchronization of desktop computers to the Coordinated Universal Time (UTC) yields numerous use cases, such as distributed measurements. Several solutions address this need, at different levels of price and accuracy. In this work we evaluate on the achievable precision in time synchronization of a desktop PC, for example, assisted by a low-budget GPS receiver. This is achieved by a novel measurement setup, which is comparing the software synchronized internal clock of the PC to a rubidium frequency standard. Our results show, that the synchronization offsets of the software clocks of all tested PCs have positive mean (time lag) in the order of 10 µs. The respective standard deviation is typically an order of magnitude lower. Thereby the unknown interrupt latency is the limiting factor for the accuracy. With this work we show that today (2011) 10 µs of precision can be achieve at very low cost.