Faster alternative to Adobe Acrobat X for PDF file printing?

I have a site for a client that uses PDF for receipt generation and hence has a LOT of print jobs passing through the system. Unfortunately, Acrobat X is DOG SLOW - taking 20 seconds to load and it has to be loaded for each receipt. Is there a faster loading alternative? I’m generating PDF 3.0 spec files with a smidge of embedded javascript to start the loading process onload. Everything works fine, just slow. Ideally I need the process to be under 10 seconds without having to resort to buying new computers (about 50 would need to be replaced - not really an option).