  We analysed Kepler data of two similar dwarf novae V344 Lyr and V1504 Cyg in
order to study optical fast stochastic variability (flickering) by searching
for characteristic break frequencies in their power density spectra. Two
different stages of activity were analysed separately, i.e. regular outbursts
and quiescence. Both systems show similar behaviour during both activity
stages. The quiescent power density spectra show a dominant low break frequency
which is also present during outburst with a more or less stable value in V344
Lyr while it is slightly higher in V1504 Cyg. The origin of this variability is
probably the whole accretion disc. Both outburst power density spectra show
additional high frequency components which we interpret as generated by the
rebuilt inner disc that was truncated during quiescence. Moreover, V344 Lyr
shows the typical linear rms-flux relation which is strongly deformed by a
possible negative superhump variability.
