Chip Shot: Introducing Brand Levels for the Intel® Atom™ Processor
Atom x3, x5, x7 branding for next-gen Intel mobile processors.
Ugh. Everyone prepare to be confused all over again. And to rescore all the tablets when AnTuTu updates to account for these new CPUs.
Mike Cane’s xBlog 
If x3, x5, x7 simply range from best energy efficiency to greatest speed, it will be simple. However, we all expect a non-linear feature set, which a linear naming convention cannot model well.