  We present the analysis of XMM-Newton observations of two X-ray luminous cool
core clusters, RXCJ1504.1-0248 and Abell 1664. The Reflection Grating
Spectrometer reveals a radiative cooling rate of $180\pm 40\, \rm
M_{\odot}\rm\,yr^{-1}$ and $34\pm 6\, \rm M_{\odot}\rm\,yr^{-1}$ in
RXCJ1504.1-0248 and Abell 1664 for gas above 0.7 keV, respectively. These
cooling rates are higher than the star formation rates observed in the
clusters, and support simultaneous star formation and molecular gas mass growth
on a timescale of 3$\times 10^8$ yr or longer. At these rates, the energy of
the X-ray cooling gas is inadequate to power the observed UV/optical
line-emitting nebulae, which suggests additional strong heating. No significant
residual cooling is detected below 0.7 keV in RXCJ1504.1-0248. By
simultaneously fitting the first and second order spectra, we place an upper
limit on turbulent velocity of 300 km$\rm s^{-1}$ at 90 per cent confidence
level for the soft X-ray emitting gas in both clusters. The turbulent energy
density is considered to be less than 8.9 and 27 per cent of the thermal energy
density in RXCJ1504.1-0248 and Abell 1664, respectively. This means it is
insufficient for AGN heating to fully propagate throughout the cool core via
turbulence. We find the cool X-ray component of Abell 1664 ($\sim$0.8 keV) is
blueshifted from the systemic velocity by 750$^{+800}_{-280}$ km$\rm s^{-1}$.
This is consistent with one component of the molecular gas in the core and
suggests a similar dynamical structure for the two phases. We find that an
intrinsic absorption model allows the cooling rate to increase to $520\pm 30\,
\rm M_{\odot}\rm\,yr^{-1}$ in RXCJ1504.1-0248.
