Review: 3 laptops powered by Intel's Core i7 processor

Intel Corp.'s new Core i7 family of processors includes the company's most advanced mobile chips. First introduced in September 2009, the design was revamped this January. The latest version of the mobile Core i7, called Arrandale during its development, is built on a 32-nanometer fabrication process and offers base speeds that range from 1.06 GHz to 2.66 GHz.

Systems equipped with the new Core i7 can deliver between two and three times the performance of a Core 2 Duo notebook. In other words, these processors and the systems built around them are meant for users who demand high performance -- and are willing to pay for it. For example, the Core i7 Extreme Edition lists for a bulk price of $1,054, whereas the Core 2 Duo processors can cost up to $619 but tend to hover more in the $300 range.

To see if the Core i7 family lives up to its billing, I gathered three new notebooks for a high-performance shootout: Fujitsu's LifeBook E780, Hewlett-Packard's EliteBook 8540w and Lenovo's ThinkPad W510.

Inside the Core i7

Intel's new processors contain 774 million transistors shuttling data back and forth on a sliver of silicon the size of a pinky nail. (In contrast, the Mobile Core 2 Duo and Atom processors found in mainstream notebooks and netbooks have up to 291 million and 47 million transistors, respectively.)

Core i7 processors come with either two or four processing cores, depending on the model (the Core 2 Duo comes with two while the Atom comes with one). Equipped with Intel's Hyper-Threading technology, each core can handle two streams of calculations. This lets the processor do four -- or eight -- tasks at once, a capability that is particularly useful when running repetitive calculations, such as in a complex spreadsheet.

Most processors stay at their set clock speed while working, but Core i7 processors can speed up for brief periods to handle particularly intense work. Called TurboBoost by Intel, this process helps the processor act like a marathoner and sprinter in one. For example, the 620M model runs at 2.66 GHz, but will speed up to 3.33 GHz if the operating system senses it needs more processing power and the chip is not overheating. As soon as it gets too hot or the computing load decreases, the chip drops back to its normal speed. It's all automatic and invisible to the user, but it means higher performance when necessary.

A critical element of the Core i7's performance is its ability to cache frequently used data and instructions within memory cells; these cells are close to the processing cores, which streamlines the processor's operation. The chip provides 64KB of Level 1 and 256KB of Level 2 cache as well as 4MB to 8MB of Level 3 cache, depending on the model. The result is that the processor spends less time waiting for data and instructions and more time working.

All this hardware has a dark side: It needs power. According to Intel representatives, while there is some spread based on the amount of cache and clock speed, the Core i7 920XM tends to use 65 watts of power. In comparison, a midrange Core 2 Duo uses about 22 watts and an Atom uses about 5 watts.

This not only drains a battery quicker than you can say "Where's the closest outlet?" but requires extra cooling from a fan or two to prevent overheating, further cutting into battery life. As a result, most Core i7-equipped notebooks also have six- to nine-cell batteries.

In addition, Core i7 laptops tend to be among the most expensive around. That's true in part because they're also among the best equipped; they're meant for those looking for heavy-duty multimedia machines for work or play. As a result, these systems can cost anywhere from about $1,500 to over $3,000, depending on what options you go for.

But you will get a significant performance boost. Even the slowest of the three Core i7 machines I tested -- the Fujitsu LifeBook E780 -- ran 63% faster in my tests than a Lenovo IdeaPad Y450 with a 2.53-GHz Core 2 Duo processor.

Buyers who are just looking for a competent system can get what they need for a lot less. But if you're buzzing through complex spreadsheets, editing high-definition video, streaming an HD movie or working with a 3D CAD model, a full-size notebook with a Core i7 processor is often the best tool for the job.