[gmx-users] RMSD graph over time and g_cluster RMSD distribution seem at odds with each other

[ms]

Dear Gromacs users,

I am analyzing the RMSD evolution of a trajectory with g_rms and 
clustering it with g_cluster (GROMOS, cutoff 0.1). I am noticing 
something quite odd in the RMSD distribution. I link here the RMSD 
evolution over time , the cluster ID over time, and the RMSD 
distribution (see http://imgur.com/a/0ftA2 ).

RMSD evolution in time and cluster ID in time seem to make sense -the 
larger cluster is cluster 1, and it indeed populates most of the 
trajectory.

The RMSD distribution is also correctly bimodal and peaked around the 
right values, at least visually. However, I would expect that the peak 
around 0.3-0.4 should be larger than the peak around 0.1, given the time 
evolution/distribution of RMSD, yet I see the opposite, apparently. What 
does it mean?

Thanks,
Massimo