I have a little problem to generate a pdf file on the version Odoo 8, i have installed a module which converts numbers in letters I had already used it in version 7, it intall well with a small change in invoice.py, the problem is that when I generate the pdf file it takes time to create the pdf about 15 seconds, here is my problem

I forgot to mentioned that the first generation of pdf file is slow after that second one becomes normal, it happens to me at every service startup Odoo if I restart Odoo first impression becomes slow, I think this is a service that starts with Odoo but I dont know what it is
thank you

im in windows