Drupal 7 Painfully Slow Performance

We recently (yes, finally) started testing Drupal 7 and there is only one word for its performance....SLOW! It seemed to load quickly on the home page after the installation but once we logged back in it was as if we were attempting to run the site on a x86 with 512MB of RAM from a USB RAID array.

This server has a dev version of Drupal 6 that screams along without any issues but the defaul Drupal 7 installation was not performing well. After some research on the web it appears the performance issues are caused by modules that provide functionality to the server and client (a.k.a. browser).

To help with client speed disable the following modules (http://yoursite.com/admin/modules/list).
- Overlay module
- Toolbar module (Disclaimer: Make sure you have installed a module which replaces the admin functionality such as the Administration menu module before disabling this module.)

Server side:
- Update Manager Module

Disabling those three modules caused a significant increase in the response time and performance of our Drupal 7 sites.

All the best.