Intel brought its mainstream desktop CPU lineup into the Nehalem era today with the launch of the Core i7 860 and 870, and the Core i5 750. Also launched today is the P55 chipset, which implements a new system architecture that represents a significant break with Intel's past. In this short article, we'll take a brief look at each, in turn.
In previous articles we've covered Nehalem's microarchitectural improvements to the Core 2 Duo lineage, so we won't recap that here. What is worth repeating, though, is that Nehalem is Intel's first x86 design to feature an on-die memory controller. This significantly changes the system topology, but in a direction that AMD already went way back in 2003.
| Processor Number | Base Clock Speed (GHz) | Max Turbo Frequency (GHz) | Cores/Threads | Cache | 1K Unit Price | SMT | TDP |
|---|---|---|---|---|---|---|---|
| Core i7-870 | 2.93 | 3.6 | 4/8 | 8MB | $562 | Y | 95W |
| Core i7-860 | 2.80 | 3.46 | 4/8 | 8MB | $284 | Y | 95W |
| Core i5-750 | 2.66 | 3.2 | 4/4 | 8MB | $196 | N | 95W |
The Core i5/i7 parts that were launched today are quad-core, with the i7 having two-way SMT for a total of eight threads per socket. The table above gives a general breakdown of the relevant features of the three new parts.
The floor plan above shows the main blocks in Nehalem, and if you've followed previous Nehalem launches (most notably Bloomfield) then you may be able to spot what's missing: there is no QuickPath Interconnect (QPI) interface. Instead, in a significant twist that differentiates Intel's new PC system architecture from even AMD's offerings, there is now a PCIe interface that enables the GPU to attach directly to the processor socket. This latter move was made in anticipation of two things: 1) the GPU will migrate right into the processor socket at a later point when Intel releases a CPU with an on-die GPU integrated into it, and 2) for a discrete GPU, Intel hopes you'll use Larrabee.
To understand what all of this means, let's look at a few diagrams.
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