Best way to handle big files in Vegas 7
 

I am working on a large project and I have 20 hours of HDV and It is all on the hard drive in 20 files ( Tape1-tape 20 ) and so far I just brought 10 hours in Vegas7 and I takes a long time to come up with all this footage.
IS there any way to make the project runs faster when I bring all the 20 hours of HDV footage ?
I don't use the media manager ( how can I turn it off in Vegas ) and would that make it any faster.
Is there any limitation on how much media Vegas can handle ?

Thanks In advance for any help.