saving posts has become very slow on WP, it now takes about 40s to save a post or page. It's a bigger site with about 3000 entries and about 2000 tags (simple tagging) for which rewrite URLs are created. But the sitemap plugin only needs 5s to create about 6500 URLs when run manually, so I doubt that's the reason behind the slowness. Saving wasn't lightning fast before, but I think it has slowed down significantly lately. I've already disabled a couple of plugins to no avail.
All other admin functions are still very fast.
Does anyone have any ideas about this?