What is the common ground for i7 processors? [closed]

"i7 is a brand name for a group of processors based on the Nehalem processor architecture by Intel. The five ""specifications"" you're referring to are code names for different versions of the i7. Each codename indicates are particular set of features, which may or may not be shared across versions.

They differ in the following areas:

The ""process size"", or the size of the smallest features etched in the silicon. As you can see from the chart, Arrandale and Gulftown are 32nm, and Clarksfield/Bloomfield/Lynnfied are 45nm.
TDP (Thermal Design Power), the maximum amount of power that needs to be dissipated by the cooling system.
Their I/O bus systems, as Bloomfield and Gulftown introduce the Intel Quickpath interconnect.
Socket type, which is the manner in which the connect to the motherboard in a system.
Their L3 cache size, although this isn't strictly divided along model lines. L3 cache is a third level of on-chip cache, which is present in advanced processors.

The ""common ground"" between them all is that they all share the Core i7-branded microarchitecture, all of which are quad-core, hyperthreaded chips (ed: except Gulftown I guess)."