The latest Intel CPUs seem to the hot topic these days and cause a bit of confusion too, those are the i3, i5 and i7, so here is a quick write up on the differences and a scrum pad for me for future lookup. Collected most of the info from the forums, Intel and the fabulous google.

Intel Core i3, i5 and i7 are the latest offerings currently on the market, and recently the Gulftown Hex core were made available for a hefty price tag for which I could assemble a top end PC.

One of the main differences with these new offerings compared to the older duo or Quads is that these have the memory controllers embedded in the processors instead of the one on the northbridge on the motherboard, this provides an increase in performance and speed as there is a reduction in the communication time between the processor and the controller on the motherboard.

CORE i3
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Clarkdale – i3 530, 540:

These are the least expensive and least powerful of the lot, they have 2 physical cores and supports Intel® Hyper-Threading Technology.
They have 2 physical silicon dies in the CPU, one for the cores and L1,2,3 caches and the other for the GPU if there is no seperate video card (normally like in a H55/57 type board), also this die has the PCIe controller and the integrated memory controller, these 2 dies are linked by a Quick Path Interface (QPI)

**All i3 CPUs work only in LGA1156 motherboard.

Core i5
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Clarkdale – i5 650, 660, 661, 670:
Identical to above, but also include the Intel® Turbo Boost Technology.

Lynnfield – i5 750:
These are Quad cores and similar to low end Core i7s, they don’t have
Intel® Hyper-Threading Technology.
Intel® Virtualization Technology for Directed I/O (Intel® VT-d)
Intel® Trusted Execution Technology

**All i5 CPUs work only in LGA1156 motherboard.

Core i7
——-
Lynnfield – i7 860, 870:
These are the low end versions of the i7 core, Quads for the LGA1156 motherboards, the main difference is that there are no 2 separate dies, the PCIe and memory controller are on the same die, so doesn’t require a QPI link.

Bloomfield – i7 920, 940, 960, 965, 975:
The mid level Nahelam Quads are for the LGA1366 motherboards, here again there is a QPI link between the PCIe controller and CPU, but the PCIe is on the motherboard chipset and not on the CPU die.

All i7s have Intel® Hyper-Threading Technology and Intel® Turbo Boost Technology.

Gulftown – i7 980:
Similar to Bloomfields, but have six cores and go on the LGA1366 motherboards.

LGA1156 and LGA1366:
Based on the above processor selection and the motherboard, you might want to choose the correct RAM, 1156 motherboards work only with DDR2 RAM and 1366 boards work with the DDR3 RAM and the corresponding CPU has either a Dual Channel or a Triple Channel memory controller built in.