It has a TDP of 4.5W. That means, the OEMs should make a thermal dissipation system that can handle 4.5W worth of heat generated, no matter how.I think i read a review of an ultrabook equipped with a broadwell cpu but with a fan installed. I could have misread but manufacturer could be trying to play safe too.
Just my opinion
Yes, that Ultrabook is called Lenovo Yoga 3 Pro. Blame Lenovo for that. Rather than designing a proper fanless thermal dissipation system, they instead opted to put a fan there, with no proper chambers, and call it a day. That's why the Y3P came significantly earlier than other Broadwell laptops.