  We report on the XMM-Newton observation of HP Cet and Swift J0820.6-2805, two
X-ray photon sources that are candidates to be members of the intermediate
polar class of cataclysmic variables. If the historical optical light curve of
HP Cet shows a periodic feature at $\simeq 96$ minutes, a clear identification
of such a signature in the high energy band (apart for a variability on a time
scale of $\simeq 8$ minutes as detected by the ROSAT satellite) is lacking. By
using XMM-Newton archive data, we clearly identify a feature (at $\simeq 88$
minutes) which is marginally consistent with one of the binary system orbital
periods reported in the literature. We also found a signature of a periodic
features on the time scale of $\simeq 5.6$ minutes. In the case of Swift
J0820.6-2805, the intermediate polar nature was previously unclear and the
orbital and the white dwarf spin periods were unknown. Here, the 0.3-10 keV
data undoubtedly reveal an orbital period and a white dwarf spin of $\simeq
87.5$ minutes and $\simeq 27.9$ minutes, respectively. The spectral analysis
showed that both HP Cet and Swift J0820.6-280 are members of the under-luminous
IP subclass since their luminosity in the $0.3-10$ keV band is estimated to be
$\simeq 5\times 10^{30}$ erg s$^{-1}$ and $\simeq 3.8\times 10^{29}$ erg
s$^{-1}$, respectively.
