@jsc well you still have a 0.5 left on multi ;]
From those several e5200s that I came across only one ran ok at 333, one wouldnt go past 305. The one i kept for myself runs ok at 330. It was an awesome cpu for the money when I bought it.
@Miguel - let me get this straight: it works fine @300 or 333 with the F4 bios?
You have to consider the possibility that you may have one of those "less capable" ones and it wont go past certain point no matter what you do. But post other settings(voltages, memory multiplier etc) maybe its something else.
Also go through this guide it can help you a lot http://www.tomshardware.co.uk/forum/page-245679_11_0.html