Centrino? Pentium M? PC Labs Looks Beyond the Name GameKonstantinos Karagiannis
Intel's much-awaited mobile CPU is here—and we are very, very impressed. Along with the supporting chipset, the new processor delivers on Intel's promise of faster performance and a battery-life boost measurable in hours.
The Pentium M—the first mobile Intel CPU designed from the ground up (instead of being engineered from an existing desktop CPU)—should reap nothing but praise. The problem is, it's likely to be met with a raft of confusion.
For starters, Intel named the new chip the Pentium M, which is bound to be confused with the faster-clocked (but not better performing) Intel Mobile Pentium 4 Processor-M family. Worse, the Centrino moniker—the new mobile-platform brand name that Intel will be pushing in its marketing—can be used on a notebook only if the notebook contains both the Pentium M (married to one of the two new Intel chipsets) and Intel's integrated wireless networking solution, the Intel PRO/Wireless 2100.
There are a number of reasons why hinging the marquee Centrino name on the wireless solution is a move that has already met with resistance among Intel's customers. First, the PRO/Wireless 2100 (a cobranded Cisco setup) currently supports only the 802.11b wireless standard. Many notebook makers have already begun offering integrated 802.11a/b combo mini-PCI solutions (as found in one of the six Pentium M systems reviewed here).
Intel won't deliver an a/b solution for months. And that's not even touching on the impending juggernaut, 802.11g (First Looks, March 25, 2003). Intel promises a Centrino 802.11g solution by year's end, while parts from other makers are available now.
Intel claims its integrated Centrino platform was designed to work as a cohesive system, and that the wireless component is an important part of the whole, not just an add-on. Also, Intel says the PRO/Wireless 2100 part was designed for maximum interoperability in a multiwireless environment (when running 802.11b and Bluetooth simultaneously, for example). For consumers, the Centrino logo on the laptop will guarantee that the wireless features will work at one of the thousands of "hot-spots"—coffee shops, airports, hotels, book stores—that are signing up for Intel's wireless-access program (and that will also display the Centrino logo).
It will be a shame if the confusion and controversy surrounding Centrino overshadow one undeniable fact: The Pentium M CPU itself is a marvel. Out of the gate, it's available in four clock speeds, ranging from 1.3 GHz to 1.6 GHz. The chip is a power saver, peaking at 1.5 volts. And it comes in two other versions: LV (low-voltage 1.1 GHz, 1.18 volts peak) and ULV (ultralow-voltage 900 MHz, 1.0 volt peak) to suit different types of portables, including Tablet PC devices.
Part of the Pentium M's efficiency comes from its ability to shift clock speed and voltage intelligently, based on the tasks it's performing. This SpeedStep implementation allows it to drop to multiple lower speed settings and bottom out as low as 600 MHz and 0.96 volts (0.85 volts in the ULV chip).
On our tests, these features worked as promised. In this miniroundup, four of the six machines we tested delivered better than 5 hours of runtime per charge. In the past, we rarely saw a portable deliver that kind of runtime without resorting to dual batteries.
Of course, users want more than just improved battery life, and this slower-clocked chip has to compete with the existing P4-M for the hearts of performance buyers.
To keep up, the Pentium M has a new microarchitecture that borders on technical wizardry. You'll find micro-ops fusion, which speeds up execution of operations by fusing them together. Advanced branch prediction efficiently plans ahead to avoid the need for extra or repeated work.
To enable faster instruction execution at the lower power levels the chip is sure to hit frequently, Intel put in a dedicated stack manager, which is an internal auditor that keeps track of tasks without interrupting itself to maintain internal accounting. Support for streaming SIMD extensions II is here, too, making the Pentium M fully compatible with P4-optimized software (although there's no Hyper-Threading support). And a real killer addition for most applications is the Pentium M's 1MB of L2 cache.
Further optimizing the Pentium M's impact are two new chipsets that Intel is launching. The 855PM is liberating and powerful, offering external 4X AGP graphics options (as did the 845 before it), while upping total memory support to 2GB of 266-MHz (or 200-MHz) DDR SDRAM and operating at less than 1 watt (less than half the draw of the 845). The 855GM draws more power, coming in at just under 2 watts, but it also integrates Intel's Extreme Graphics 2, an affordable solution for budget notebooks.
In testing, the Pentium M systems did very well when compared with P4-M laptops. For example, a 1.4-GHz Pentium M unit easily beat out a 2.4-GHz P4-M system on our Business Winstone and Multimedia Content Creation Winstone tests. On Business Winstone, the Acer unit (the fastest of these Pentium M portables) scored 31.9, a 38 percent increase over the 2.4-GHz P4-M's score of 23.2.
Here we review 1.6-GHz Pentium M–based notebooks from Acer, Dell, Gateway, IBM, and Toshiba, as well as a 1.4-GHz machine from HP Compaq. All six feature the 855PM chipset, but only the Acer, Gateway, and Toshiba are true Centrinos, using the Intel wireless solution.
More than delivering on its promised performance and battery life gains, the Pentium M is currently the way to go for the ultimate mobile computing experience. Look for the chip's logo or name in a system's specs when shopping. For now, though, don't worry about whether the Centrino logo is there as well. For certain wireless applications, you may be better off without it.
Copyright © 2004 Ziff Davis Media Inc. All Rights Reserved. Originally appearing in PC Magazine.