I've experienced slow admin/internal UIs that were so slow and inefficient they brought down the consumer site... and yes, I'm talking algorithmically. Processing data in triple nested loops because it was "quick and easy" and then the data grew beyond a relatively small threshold (something like 10k records was where it started to break).
Sorry, what's the context? Admin / account and login areas don't care / matter much, because they want it :p they'll wait...