Overview
The Core i7 modifies the landscape quite a bit, but much of what you need to know about it is apparent in the picture of the processor die below, with the major components labeled.
What you're seeing, incidentally, is a pretty good-sized chip—an estimated 731 million transistors arranged into a 263 mm² area via the same 45nm, high-k fabrication process used to produce "Penryn" Core 2 chips. Penryn has roughly 410 million transistors and a die area of 107 mm², but of course, it takes two Penryn dies to make one quad-core product. Meanwhile, AMD's native quad-core Phenom chips have 463 million transistors but occupy a larger die area of 283 mm² because they're made on a 65nm process and have a higher ratio of (less dense) logic to (denser) cache transistors. Then again, size is to some degree relative; the GeForce GTX 280 GPU is over twice the size of a Core i7 or Phenom.
Nehalem's four cores are readily apparent across the center of the chip in the image above, as are the other components (Intel calls these, collectively, the "uncore") around the periphery. The uncore occupies a substantial portion of the die area, most of which goes to the large, shared L3 cache.
The Core i7 can get to main memory very quickly, too, thanks to its integrated memory controller, which eliminates the chip-to-chip "hop" required when going over a front-side bus to an external north bridge. Again, this is a familiar page from AMD's template, but Intel has raised the stakes by incorporating support for three channels of DDR3 memory. Officially, the maximum memory speed supported by the first Core i7 processors is 1066 MHz, which is a little conservative for DDR3, but frequencies of 1333, 1600, and 2000 MHz are possible with the most expensive Core i7, the 965 Extreme Edition. In fact, we tested it with 1600 MHz memory, since this is a more likely configuration for a thousand-dollar processor.
For a CPU, the bandwidth numbers involved here are considerable. Three channels of memory at 1066 MHz can achieve an aggregate of 25.6 GB/s of bandwidth. At 1333 MHz, you're looking at 32 GB/s. At 1600 MHz, the peak would be 38.4 GB/s, and at 2000 MHz, 48 GB/s. By contrast, the peak effective memory bandwidth on a Core 2 system would be 12.8 GB/s, limited by the throughput of a 1600MHz front-side bus. With dual channels of DDR2 memory at 1066MHz, the Phenom's peak would be 17.1 GB/s. The Core i7 is simply in another league. In fact, our Core i7-965 Extreme test rig with 1600MHz memory has the same total bus width (192 bits) and theoretical memory bandwidth as a GeForce 9600 GSO graphics card.
The upshot of all of this is that a single Core i7 processor supports a total of eight threads, which makes for a pretty wicked looking Task Manager window. Because of the resource sharing involved, of course, Hyper-Threading won't likely double performance, even the best-case scenario. We'll look at its precise impact on performance in the following pages.
The changes to Nehalem's cores don't stop there, either. Intel has improved the performance of the synchronization primitives used by multithreaded applications, added a handful of instructions known as SSE 4.2—including some for string handling, cyclic redundancy checks, and popcount—and introduced enhancements for hardware-assisted virtualization. There's too much to cover here, really.
If you want more detailed information, see techreport.com for full repor about intel core 2 i7.
Source: techreport.com