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Intel's new Core i7 and Core i5 processors explained
Lynnfield desktop CPUs put through their paces.
By David Murphy | PC World
Published: 14:32 GMT, 08 September 09
Intel's two new Core i7 CPUs (860 and 870) are mid-range counterparts to its top-of-the-line Core i7 900-series chips, and initial tests (using Intel's new DP55KG motherboard) indicate their performance follows suit. Our early tests also show the new entry-level Core i5 750 is the one to watch when it comes to best bang for your buck.
Intel's full processor breakdown - including the axing of its Core i7 940 processor - includes some potentially confusing differences between the chips. So here's what you need to know.
The existing Core i7 900-series processor lineup, codenamed Bloomfield, now features three separate products: 3.33-GHz Core i7 975, 3.06-GHz Core i7 950, and 2.66-GHz Core i7-920 processors. Between the Core i7-950 and Core i7-920 processors sit the new "Lynnfield" 2.93-GHz Core i7 870 and 2.8-GHz Core i7 860 processors. The brand-new, 2.66-GHz Core i5 750 CPU is a Lynnfield chip as well, but we'll get to that odd duckling further below.
Technology Differences
Intel took a big leap forward in the design department when it launched Core i7 900-series processors last November. Just a few of these included a new triple-channel memory controller integrated into the chip, a new QuickPath Interconnect system to replace (and improve upon) the front-side bus architecture of old, and the return of hyperthreading that split the chip's four physical cores into eight virtual cores for increased system performance. As the Core i7 900-series chips were based on a new Intel X58 chipset and LGA1366 socket, aspiring upgraders had to invest in new motherboards to reap the benefits of the Core i7 900-series platform.
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That part still rings true for the new Core i7 800-series and Core i5 CPUs. All three run on Intel's latest P55 chipset and LGA1156 socket, which necessitates a new motherboard purchase for use. What's changed, however, is that the Core i7 800-series and Core i5 CPUs each adopt different permutations of the fanciest of the Core i7 900-series' features.
All three chips have dropped down from a QuickPath Interconnect and triple-channel memory controller to a Direct Media Interface and dual-channel memory controller. But don't freak out. This is more a loss of future-proofing than anything else given the minute performance differences between current dual- and triple-channel memory configurations.
An integrated PCI Express graphics controller on the Lynnfield CPUs can either deliver 16 lanes of bandwidth to a single PCI Express 2.0 videocard or split this connection into two x8 lanes for an SLI or CrossFire setup. Although it's a cut from the full 32 lanes (for a dual 16x or quad-8x configuration) provided by Core i7's X58 chipset, the bandwidth reduction should only affect those crazy enough to SLI or CrossFire dual-GPU videocards on a Lynnfield setup.
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