I'm downloading a pretty large update (nearly 4GBs @ 190 hours estimated time) to my office computer (a Mac Pro w/ large display) and I would like to shut off the screen display, yet leave the computer on over the weekend. Reason being is that I am the only Mac in the entire building and well...lots of curious, lookie-loos like to salivate over my machine. Usually, I simply Log Out every night.
I wouldn't even consider downloading if your internet connection is that bad that 4GB takes 190 hours (8 days).
4GB is less than an hour.
Wait until the connecivity is normal again or download in another place where you have strong internet (do it on a friend's computer and save it on a stick).