The ES suffix states that the cpu is an engineering sample.
They are the first cpu`s to roll of the fabrication process of a cpu fabrication plant.
either using a new node process or cpu architecture.
And are used for testing purposes for cpu manufacturers such as Intel or Amd.
The QBPK part of the code will denote how many cpu cores the package has.
I think it denotes it is a Haswell engineering sample cpu an with two cores.
http://cdn.cpu-world.com/Images/uploaded/0000/98/L_00009815.jpg
Just checked, it is an i3 Haswell cpu with two cores and four threads.
Not to bad for free cpu.