Intel's New Core i7 and Core i5

Intel's New Core i7 and Core i5 Processors Explained

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.

Turbo Boost: Automatic Overclocking

The new Core i7 800-series CPUs and the Core i5 750 still support the same automatic overclocking functionality, or Turbo Boost, as the Core i7 900-series processors. However, this feature has been jacked up on the newer chips. Core i7 900-series CPUs will only increase their multipliers to a maximum of two additional steps according to system demands (effectively taking a 3.33-GHz processor to 3.6-GHz depending on how many cores are in use). The new Lynnfield processors are able to jump up five multiplier steps for the 800-series chips (taking a 2.93-GHz processor to 3.6-GHz) and four for the Core i5 750 (2.66-GHz to a maximum 3.2-GHz).

Performance

Both Core i7 800-series processors support hyperthreading the same as their Core i7 900-series brethren. The Core i5 750 does not-its four physical cores are all that will appear in your operating system's task manager. Even so, the CPU's noteworthy performance makes it an excellent value for its roughly $200 price. We only saw a performance difference of 5 percent between the Core i5 750 and the roughly $555 Core i7 870 (based on WorldBench 6 testing of the two CPUs on identical system builds). In fact, the Core i5 750's score of 127 falls right around the scores set by competing Value and Power PCs that use Core i7 920 processors.