Slow parsing of OWL file

[nilskre]

Hello,
in my case the parse process is quite slow. I have a rather large OWL file, which contains the full snomed ct ontology (500 MB, 9464769 lines).

I parse it in the standard way:

g = rdflib.Graph()  
g.parse(ontology_file, format="application/rdf+xml")

This takes around 8 minutes.

Is it expected, that it takes that long?
And is there maybe some way to speed this up?

Thanks in advance!