What did 3DMark03 detect your core speed as? Also, when you are posting and you forget something, just edit your last post unless somebody posted after it. That makes the thread easier to follow.
I think that you should be getting a higher score than that on 03, especially if it was oced that high. It sounds to me that it applies the settings then when you run something that uses the speeds, it figures out that it can't use them that high, and then drops the clocks to a stable point, such as the 2D speed. That is exactly what my FX5700LE did when I could set my core speed to 1GHz on the core with stock cooling. Everything detected it at that speed, but my scores didn't improve. I later figured out that the card was just dropping speeds down.
If there is an option for it, set your 2D speed to that speed, not just your 3D speed. If you can do that, it will most likely lock up.