Nope. My initial wall was 238 BCLK, roughly 5ghz. A few tweaks and I blew past it. Now my wall is around 245ish BCLK. I dunno how I hit 249 BCLK that one time but I did. I need to go back and try highest BCLK with my lower VTT trick.
You could just have two BCLK unfriendly chips there. What multiplier you trying to use and at what BCLK? I read that certain multipliers don't play nice. You can also post what settings you are using here or start a thread on it. Here are the settings I am interested in seeing that you are trying to use.