Admin pages including content edit are exremely slow
best answer: You need to profile the PHP code in order to see what is causing the slowdown. Also check firebug to see if anything is taking a long time to download. Go through all the slides  from my DIY Drupal 7 Performance presentation.

quick answer: You can try the first 4 patches listed in the Performance wiki as these are things that I identified on our setup as being slow.