I am using a PHP Class wrapper around wkhtmltopdf from https://github.com/mikehaertl/phpwkhtmltopdf, it works fine, but on the first call takes up to 15 seconds, the others takes only 1 second in average. If I convert the files directly from the cmd it works fine as well but when the call is through the php Wrapper it does takes the time previouly mentioned. Why is this happening?, is it the garbage collector recyling all variables or other stuff?? NOTE: I have a x64 machine on an EC2 instance, I installed latest wkthmltopdf version for x64, also try x86 and the same happens.