Guide to Laptop Processors

The heart of any computer is the processor or CPU for short(central processing unit). There are quite a few brands and types of CPU's available for laptops and trying to pick the right one can be confusing.

There are laptops that use desktop versions of the Athlon XP and Pentium 4, these are good for desktop replacements where battery life is not a concern. The advantage is speed and lower cost in exchange for heat and shorter battery life. The extra speed is due in part to a faster front side bus and sometimes higher speed memory that the desktop processors support.

Below is a list of the more common laptop processors available. (note: 1 GHZ = 1000 MHZ)

Intel Processors

Trying to make sense of all the pentium variations out there? Here's a rundown of what's available and their characteristics.

Intel Pentium M

Part of the Centrino package, this mobile processor from Intel is quite an improvement over the other Mobile Pentium 4 processors.

There are many variations of this Pentium M currently available, the earliest models have 1 MB of level 2 cache, the second generation has 2 MB of level 2 cache, and the latest has added 533 Mhz front side bus support.

Pentium M processors may run at slower GHZ operating speeds than the Pentium 4 counterparts, but they still perform as good or better while providing superior battery life savings.

You may have wondered what exactly the difference is between the 755, 715, 745, 760 etc, the 7xx naming convention is new from Intel to differentiate performance levels without relying on the operating speed numbers (similar to AMD's use of performance rating instead of actual speeds). See link below for details.

Pentium M ratings, speeds, and power requirements.

Intel Celeron M

The Celeron M is basically identical to the Pentium M mentioned above except for a few differences. The level 2 cache has been reduced to 512KB or 1MB (depending on the generation of the processor) and the maximum speed is currently in the lower range of 1.5GHZ and BELOW.

These processors have also recently inherited the new model number naming system Intel is using such as Celeron M 310, 320, 330, 340.

Celeron M ratings, speeds, and power requirements.

Mobile Intel Pentium 4 518, 532, 538

Based on the prescott core, these can be considered a small evolutionary step above the below mentioned processor. Besides the new naming convention(532, etc), these processors include SSE3 instruction support and increased level 2 cache of 1 MB (previously 512KB).

Mobile Intel Pentium 4

Laptops with these CPU's are usually used as replacements for bulkier desktop computers, they're great for video editing, 3D gaming, or any other task that requires hefty processing power.

The main difference from a desktop Pentium 4 would be somewhat better thermal properties and lower power consumption. The speeds are similar to desktop P4 processors so the easiest way to currently determine if a laptop is using a desktop P4 or the Mobile P4 is to check the FSB(front side bus) speed. 800 MHZ FSB = desktop P4 (currently), 533 MHZ = Mobile P4 (harder to tell at CPU speeds below 2.8 GHZ due to older desktop P4's not supporting 800 MHZ FSB).

The higher end models above 2.66 GHZ support Intel Hyperthreading technology.

Mobile Intel Pentium 4-M

The Pentium 4-M is available at speeds up to 2.6 GHZ. The difference between Mobile Pentium 4 and the Pentium 4-M is the 4-M does not support Hyperthreading, uses less power, and runs cooler.

Laptops based on this processor perform in the mid-range between the Celeron based laptops and the Centrino and Hyperthreading enabled laptops. The Pentium's mentioned above are recommended over this one since they offer better performance or battery life at equal or better prices.

Mobile Intel Pentium 3-M

Found mainly in older, used, or refurbished laptop computers, the mobile Pentium 3-M processor is still VERY capable for most users needs. Most laptops based on this CPU are quite small, lightweight, and have a fairly good battery life.

Highest speed is up to 1.33 GHZ but 1.2 GHZ is more common.

Mobile Intel Celeron

Generally found in inexpensive laptops with speeds up to 2.4 GHZ. Performance is good for running office applications and other light duty tasks. Even though GHZ speed is right up there with the Pentium 4, it isn't quite as powerful due to smaller on-chip cache memory.

SpeedStep Power Management

All Mobile Pentium's, with the exception of the Celeron's, have “SpeedStep“ technology which lowers the CPU speed and power consumption during periods of inactivity or when running applications that do not require much power. SpeedStep generally has only two settings, low power mode and maximum power mode, Enhanced SpeedStep may have up to five operating speeds or modes to best balance energy saving and processor speed.

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AMD Processors

AMD based laptop computers aren't as confusing in my opinion, besides deciding between the low end CPU and the high end CPU all you need to know is what other features you would like such as screen size, hard disk capacity, etc.

AMD Mobile Duron

The low end or budget processor, available at speeds up to 1.3 GHZ. Inexpensive and great performance for its price range.

AMD Mobile Athlon XP-M

The replacement for the previous Mobile Athlon 4 processors, it includes improvements and doubles some of its cache memory.

The Athlon XP-M laptop computers are usually less expensive than their Pentium counterparts but offer as good or better performance.

AMD Mobile Athlon 64

The Mobile Athlon 64 is currently available in some desktop replacement laptops. It is the Athlon 64 core with optimized power and thermal characteristics designed for desktop replacement laptops.

Speed varies depending on the application but it is comparable to the top end desktop processors in most applications. It should be noted that the performance may get even better when software applications actually support the 64 bit design of the Athlon 64.

The nice thing about this CPU is it supports both SSE2 (previously only found on the P4 and Pentium M) and 3DNow! instructions. Software optimized for either of these instruction sets get a nice boost in performance compared to processors which lack them.

PowerNow! Power Management

All mobile AMD processors include a form of power saving technology called PowerNow! It is more advanced than SpeedStep on the Intel processors because it can have up to 32 settings instead of only two.

The processor changes speed and power consumption depending on how much an application needs, the changes happen so fast you don't notice it. When you need full power you will get it, when you're just working on a document it will throttle down without you noticing any difference in performance. Most manufacturers only use about 4 PowerNow! settings that covers most application needs.

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