Dianne: That's what seems to have fixed it for me; Go to System ->Administration->Software Sources (or System->Administration->Update Manager->Settings) On the first tab, "Software Sources" (in 10.10) look at the list Download from: hit other, then try hitting the "Select Best Server", which I think pings a bunch of mirrors to find the one with the lowest latency (~ closest to you). See if that helps, then try something sensible off the list.
Dianne: That's what seems to have fixed it for me; Go to System ->Administratio n->Software Sources (or System- >Administration ->Update Manager->Settings) On the first tab, "Software Sources" (in 10.10) look at the list Download from: hit other, then try hitting the "Select Best Server", which I think pings a bunch of mirrors to find the one with the lowest latency (~ closest to you). See if that helps, then try something sensible off the list.