  We study the thermal phase transition of the bosonic BMN model which is a
mass deformed version of the bosonic part of the BFSS model. Our results
connect the massless region of the phase diagram described by the bosonic BFSS
model with the large-mass region, where the model is analytically solvable. We
observe that at finite value of the matrix size $N$, the critical region is
smeared over a small temperature range. The model has a single critical
temperature, which arises as the large $N$ limit of two apparent transitions at
finite $N$. We emphasise the vital role played by finite $N$ corrections in the
confined phase and illustrate this with a novel treatment of the noninteracting
Gaussian model.
