Intel's Core i7 gets put to the test

Intel won't announce its new Core i7 chips until later this month, but the first real reviews are popping up all over the place today. Based on the early previews, I expected to see good numbers and Core i7, formerly known as Nehalem, delivers.

These first Core i7s are Bloomfield processors designed for high-end desktops. There are three versions corresponding to different market segments: the 3.2GHz Core i7 965 Extreme Edition ($999), 2.93GHz Core i7 940 ($562) performance part, and the more mainstream 2.66GHz Core i7 920 ($284).

The new Core i7s are all quad-core processors (four cores on a single die) and each core can handle two threads. They also have an integrated memory controller and a new three-level cache, including an 8MB shared L3 cache. All of that adds up to a relatively hefty chip with 731 million transistors and a die size of 263 square millimeters. By comparison, a dual-core Penryn Core 2 Duo, which uses the same 45nm process technology, has 410 million transistors and measures 107 square millimeters. AMD's current quad-core Phenoms--a more accurate comparison since they have four cores and a similar architecture--are even larger at 283 square millimeters, but it is still manufactured at 65nm. AMD's 45nm Shanghai server processors--also expected later this month--will reportedly be nearly identical in size to Nehalem.

Though it is based on the same process as Penryn, the list of new features is long. Core i7s have three memory channels that support 1,066MHz DDR3; a new high-speed system bus, Quick Path Interconnect (QPI), that connects the processors to other system components (and to one another in multi-socket systems); a new socket; a new supporting chipset (the X58); more sophisticated power management features; a Turbo Mode that transparently pushes more power to the active core when running single-threaded applications; and new SSE instructions.

The results look very good. The Core i7 is the fastest desktop processor across the board on mainstream applications, multimedia tests, games and workstation applications. It looks like the second time's the charm for Hyper Threading since the performance is especially impressive on applications that can take advantage of simultaneous multi-threading such as video encoding, 3D graphics rendering, and file compression and encryption. On some tests, the sub-$300 Core i7 920 outperformed the current Penryn 3.2GHz Core 2 Extreme QX9770, which sells for $1,399. The current Penryns were already faster than AMD's fastest quad-core, the 2.6GHz Phenom X4 9950 BE, and Core i7 pads Intel's lead. Shanghai should close the gap a bit, but at this point it's hard to see how AMD can catch up anytime soon.

For now, the Core i7 and X58 are strictly for high-priced desktops, but that will soon change. Next year Intel will release server versions, currently known as Nehalem-EX, and eventually more quad-core and dual-core versions for both desktops and laptops. By late 2009, some desktop and mobile packages will also include integrated graphics processing units.

Intel Core i7 reviews coverage:

• Intel Core i7-965 Extreme Edition [CNET Reviews]
• Intel's Core i7 processors: Nehalem arrives with a splash [The Tech Report]
• Intel Core i7 Review: Nehalem Gets Real [ExtremeTech]
• Intel's Core i7 920, 945 & 965 processors [bit-tech.net]
• Intel Core i7 'Nehalem' processor and X58 chipset [The Register Hardware]
• First Look: Intel's Nehalem Smashes Performance Thresholds [ChannelWeb]
• Falcon Northwest Mach V [PC Magazine]