  We use Rossi X-ray Timing Explorer observations to conduct a population study
of the timing properties of accretion-powered neutron star Low Mass X-ray
Binaries (LMXBs), following a model-independent approach that was originally
applied to black hole systems. The ratios of integrated power in four equally
spaced Fourier frequency bands allow power spectral shapes to be parameterised
with two `power colour' values, providing a simple way of tracking the
evolution in timing properties across observations. We show that neutron star
LMXBs follow a remarkably similar power spectral evolution to black hole LMXBs,
confirming that the broadband noise variability seen in both types of system
has a common origin in the accretion flow. Both neutron stars and black holes
follow a similar clear track in the power colour-colour diagram as they
transition from the hard through soft states. Quantifying the position on this
oval track using a single parameter, the power-spectral `hue', we find that the
transition in X-ray spectral shape occurs at the same hue for both neutron star
and black hole systems. The power colours of Z sources map on to those of soft
state black holes, while those of atoll sources correspond to all spectral
states. There is no clear dependence of power colour on neutron star spin, or
on whether the neutron star is clearly magnetised (determined by ms X-ray
pulsations).
