  Observations on galactic scales seem to be in contradiction with recent high
resolution N-body simulations. This so-called cold dark matter (CDM) crisis has
been addressed in several ways, ranging from a change in fundamental physics by
introducing self-interacting cold dark matter particles to a tuning of complex
astrophysical processes such as global and/or local feedback. All these efforts
attempt to soften density profiles and reduce the abundance of satellites in
simulated galaxy halos. In this contribution we are exploring the differences
between a Warm Dark Matter model and a CDM model where the power on a certain
scale is reduced by introducing a narrow negative feature (''dip''). This dip
is placed in a way so as to mimic the loss of power in the WDM model: both
models have the same integrated power out to the scale where the power of the
Dip model rises to the level of the unperturbed CDM spectrum again. Using
N-body simulations we show that that the new Dip model appears to be a viable
alternative to WDM while being based on different physics: where WDM requires
the introduction of a new particle species the Dip stems from a non-standard
inflationary period. If we are looking for an alternative to the currently
challenged standard LCDM structure formation scenario, neither the LWDM nor the
new Dip model can be ruled out with respect to the analysis presented in this
contribution. They both make very similar predictions and the degeneracy
between them can only be broken with observations yet to come.
