Originally Posted by alykins
are you viewing a cached page? your "it used to be 850px..." tells me that it is probably retaining an old value. clear cache and check it.
Going off of alykins comment, CTRL + SHIFT + DEL(ETE) will show you the option to reset/clear cache option on most browsers. If you did not know
Checking through my browsers they appear fine on all of them. (FF3.6).