Adobe file size

[Jim25762128hoqa]

I have a graphics dept that has pdf files over 300MB that they struggle to open/work with. It can take over 10 minutes to open. I have had smiliar times on laptops, PCs, an iMac, and a server running 32bit and 64 bit. Is 300MB considered a large pdf file? I am reaching out to see if t his is a file we created or something that was sent to us. If this file was sent to us, is it reasonable to ask the sender to reduce the file size? I believe the file size of the files used in this department are a runaway train. File size needs to be a consideration not only for the usablity of the file but storage as well. 

Please let me know if there is anything I can check and whether 32bit/64bit should make a difference.