Turn off revisions in Wordpress 2.6

Some of my other activities are hosted on Wordpress, so when I updated to 2.6 last week I was rather surprised with the amount of speed lost to revisions. I wanted to turn this off, so this is what I did:

# add these to your wp-config.php file.
#
// disabel revisions and slow down the saving!
define('WP_POST_REVISIONS', false);
define('AUTOSAVE_INTERVAL', 120);

The second line is for saving drafts, but I hate that too!