I am currently using Ubuntu 14.04 LTS, alongside Windows 7. I have some big and heavy pdf documents, nearly 70-80 MB. On some suggestions throughout the internet, I downloaded MuPDF. But MuPDF fails to open those heavy pdfs. Though the default Document-Viewer opens them, it is too heavy on processing and RAM. I opened same pdf in Windows7 using Foxit, and yes, it works less on processor and RAM too; so I didn't felt like going along with default document-viewer of Ubuntu.
So please suggest me a good PDF viewer, which can handle heavy pdfs and is lighter on the system (processor, RAM).