[generationP]

SumatraPDF on Windows is lightning fast with the kind of PDFs you get from the arXiv (true PDFs without heavy graphics). I don't know what is fast on Linux, but probably some MuPDF-based viewers are (the MuPDF PoC viewer is fast even on WSL).

[btdmaster]

zathura is superfast on Linux, can handle thousands of pages, and may be used under either MuPDF or poppler.