They must have really early ES in their hands like many vendors. I have heard similar results from my contacts and they couldn't even reach 5GHz.
We can forget those results :D
Latest ES and retail CPU's are totally different story.
Here is maximum MHz shot from today's tests. I used aircooling and fan was on low speed, cause higher speed didn't help. Those who asked about low HT link speed and NB speed have their answer here. On air you can play with these values without changing any voltage except vcore. My memory kit is some 18€ 2x1GB kit, so I can't tighten timings :D
Attachment 90812
Sorry! I had to took off some stuff just to be sure, that I'm not violating NDA ;)