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Notebook computers - know your numbers
So you're buying a new laptop computer. You've picked the colour, screen size and design you want, but the dizzying array of internal specifications is giving you a headache. You don't want to get a pretty-looking dud, however, so it's worth learning a little about the innards of the computer before you make your final purchase.
The processor
Nothing matters more when it comes to the performance of your laptop than the processor it uses. The processor is the brains of the computer, the part that does all of the thinking, from calculating Excel tables to controlling the artificial intelligence of enemies in a 3D game.
Choosing the right processor can be a challenge, however. You'll want to get one that's fast enough to do everything you want your notebook to do. You'll also want to give yourself a little headroom for the future. Unlike the hard disk and memory, the processor is very difficult (if not impossible) to upgrade later so you don't want to scrimp on the processor when you buy the PC.
If you're evaluating a laptop processor, we'd suggest starting by looking at the model series or architecture, which broadly determines what kind of tasks the laptop is suitable for. Then check to see how many cores that processor has. Then finally look at the speed rating in gigahertz of the processor.
Architecture
The first and easiest way to distinguish processors from each other is through their model type or 'architecture'. Intel produces a variety of processor architectures for different types of notebooks. Some are high-speed but use more power; others may not be as fast but use less power.
In a rough order of performance, from lowest to highest, Intel currently sells these models:
- Atom - used primarily in small "netbook" computers like Asus' Eee PC, Atom delivers enough power for basic tasks like Web browsing and productivity applications, but it's not designed for more intensive tasks like video editing or 3D gaming.
- Celeron - like Atom, Celeron is designed for smaller computers with modest processing power. A Celeron notebook can generally handle a bit more than an Atom, and may be able to even play some 3D games, but it's not for performance users.
- Pentium - The Intel Pentium processor is the classic and reliable choice for basic computing tasks.
- Core 2 Duo - a rather more powerful processor than the Celeron, the Core 2 Duo is the same processor used in many desktops. It should be capable of most computing tasks, including advanced multimedia and gaming. If you want a notebook that will fully replace a desktop computer, look for a Core 2 Duo or better.
- Core i5 - a new processor from Intel, the i5 is an update of the Core 2 architecture. You can expect an i5 processor to perform as good as or slightly better than a Core 2.
- Core i7 - the fastest notebook processor currently available, it's great if you want maximum performance for multimedia tasks.
Cores
A processor also comes with a given number of 'cores'. Each core acts as a separate processor, so a processor with four cores is actually like four processors built into one - and your computer's operating system will even detect it as four separate processors even though it's a single chip.
Current processors come with between one and four cores. The more the better, although the distinction is not as simple as saying that a processor with four cores (a quad-core processor) is twice as fast as one with two cores (a dual-core). Having more cores doesn't reallycan mean that your computer does things faster, but more importantly: it means that it can do more things at once. What this means in practice is extra cores won't make your 3D game, for example, run muchany faster, but they will allow you to play a 3D game while copying files in the background or having a Skype conversation.
If you're somebody who likes to open a lot of programs at once, then you should definitely look at a quad-core processor.
Gigahertz and cache
Finally we come to the speed of the processor, which is usually listed in gigahertz (GHz) and occasionally megahertz (MHz, where 1000 MHz=1GHz). The gigahertz rating of the processor is an indication of how fast it thinks.
Each processor also has a cache, which is a type of super high-speed memory that's built into the processor and separate from the main system memory (see RAM below). The bigger the cache, the less the processor has to call on the slower system memory.
Intel has a wide array of gigahertz/cache combinations, each denoted by a separate model number. For example, the Intel Core i7-720QM runs at 1.6GHz and has a cache of 6MB, while the Intel Core i7-820QM runs at 1.733GHz and has an 8MB cache.
Fortunately, you usually don't have to figure this out yourself. Most sellers will list the GHz rating and cache along with the model number. Our suggestion is to just ignore the model number and cache size and look at the GHz rating and get the fastest processor that's in your price range.
You should note, however, that gigahertz is not comparable between different processor architectures. A 1.6GHz Core i7 processor is much faster than a 1.6GHz Atom, because the Core i7 has intelligence built in that allows it to do more at once. Likewise, a 1.6GHz quad core processor is likely to serve you better than, say, a 1.8GHz dual core. That's why you should choose your architecture and core count first.
Memory (RAM)
A computer's memory or RAM is its "thinking space". It's where it holds the programs that are currently running and the data that's being used right now. When you try and open too many programs and documents for the memory to handle, what happens is that the computer then turns to "virtual memory" which is where it pretends that the hard disk is also RAM. Using virtual memory really slows a computer down - you'll see the hard disk light flashing wildly and it will likely take a long time to switch between applications or get anything done.
To avoid that happening, we'd suggest a computer with at least 2GB (that's gigabytes) of memory. Getting more - 3 or 4GB - doesn't hurt, but you do get diminishing returns on extra memory beyond 2GB.
Like processors, memory also comes in different speeds (also rated by MHz/GHz) and models (DDR2/DDR3). While faster memory will improve the performance of your laptop, it's not a huge factor and it's not something we'd generally worry about unless we were trying to build the ultimate performance laptop.
The hard drive
The hard drive is where your laptop files away programs and documents for permanent storage. Unlike RAM, the hard disk remembers things even when the computer is powered down. The size of the hard disk, measured in gigabytes (GB) or terabytes (TB, where 1000GB=1TB) determines how much data your notebook can store.
You don't need that big of a hard disk in your notebook unless you plan to store a lot of multimedia on it. Regular Word documents and Excel spread sheets don't take up much space. But videos do, and having lots of pictures and music files can also take up a lot of hard drive space.
For most people, 320GB or even 160GB should be plenty. You can always add an external hard drive later if you really need to, and such external drives are very cheap now - you can get 500GB for less than $100.
We should also take a moment to talk about new solid-state hard drives and traditional hard disks. Solid-state drives