OpenCPN 2.3.x Much Slower than 1.3.6?

[lfabio]

Folks,
I've been noticing something: even on PCs that are significantly faster than any laptop/boat PC, the 2.x series, from the 2.1 betas to 2.3.1 included, is embarassingly slow compared to 1.3.6, to the point of being unusable. The situation is marginally less bad in XP than in Seven, but it's very bad on both. For reference, I am using CM93v2 maps, having them on a local drive or on a network drive does not seem to change the situation. The level of zoom, however, does, insofar as when I zoom out the speed gets worse and worse. I have vector detail level 0, text enabled and MarinersStandard view with four colours. Has anyone else run into the issue?