Take a look at the answers to this question:
How can I get apt to use a mirror close to me, or choose a faster mirror?
I use the recommendation from an answer to that question to add the two lines below to the top of
/etc/apt/sources.list. This is supposed to encourage the update process to automatically pick a download mirror with better performance. I think it helps.
deb mirror://mirrors.ubuntu.com/mirrors.txt precise main restricted universe multiverse
deb mirror://mirrors.ubuntu.com/mirrors.txt precise-updates main restricted universe multiverse
- Note: The lines above are meant to used with the
/etc/apt/sources.list for 12.04 (Precise Pangolin). For earlier releases replace
precise with the release's corresponding codename.
Lucid (10.04), Maverick (10.10), Natty (11.04), Oneiric (11.10)