I'm sorry I should have been more clear.
There were problems with the P4T533 series mainboards. The initial batch of boards, carrying serial number 27xxx would often be unstable at even stock 133Mhz FSB.
Later boards remained "unrevised" -at least offcially, and continued to be of the 1.03 revision. However, the serial numbers of the newer boards did change. Very tellingly, there were last-minute modifications made to these boards, visible to the naked eye. One of these was a resistor soldered to the back of the board near the memory slots, another was the addition of a fan to the northbridge heatsink.
The point of all this is that you could have a problematic board, without really knowing it yet, and then get stuck while you are trying to OC. I've had that experience too, so it is with great empathy that I can tell you it sucks.
So what I'd recommend is checking your serial number beforehand (it can be found on a sticker on the box, very conveniently) and exchange the board if it carries the 27xxx serial, where xxx is any digit or letter, and it exhibits stability problems. 28xxx, 2Bxxx, 2Axxx and other serials are supposed to be OK. If the serial seems fine (and/or you can locate the 'mods' I talked about), and the board is at least stable at stock, then have fun overclocking.
BTW Batboy was right in that there is no fixed max frequency for any serial; it will still be trial and error, but knowing the suspect numbers may at least prevent headaches later on.