  We present a Principal Component Analysis for a hydrodynamic simulation and
compare with CMS experimental data. While the results are reasonable for
anisotropic flow, for multiplicity fluctuations they are qualitatively
different. We argue that this is due to too large transverse momentum ($p_T$)
fluctuations and $N-p_T$ covariance in the simulation than seen experimentally.
In turn this is related to too large initial size fluctuations.
