lostandwandering :
I don't believe any of the 920's should be Bloomfield. The older i7 920, 940 and 965 were Nehalem based while the newer i7 930, 950 and 975 are Bloomfield chips
You have no clue, Nehalem is the General Architecture and Die size, in Nehalem's case it refers to Core iX 45nm.
Bloomfield is features and number of cores, 'Bloom' referring to the processor having a triple channel IMC, and 'field' referring to the fact that it is a Quad core processor.
so you have, Nehalem -> Bloomfield, Lynnfield and Gainestown.
In Lynnfield, 'Lynn' refers to the processor using the 45nm die size, having onboard controllers and having a dual channel IMC.
Then in Gainestown, 'Gaines' refers to having the same features as Bloomfield, except it can use ECC memory. and 'Town' refers to it being a Server CPU and that it can be either a dual or quad core processor.