  We study the comparative importance of thermal to non-thermal fluctuations
for membrane-based models in the linear regime. Our results, both in 1+1 and
2+1 dimensions, suggest that non-thermal fluctuations dominate thermal ones
only when the relaxation time $\tau$ is large. For moderate to small values of
$\tau$, the dynamics is defined by a competition between these two forces. The
results are expected to act as a quantitative benchmark for biological
modelling in systems involving cytoskeletal and other non-thermal fluctuations.
