How It Works: Motherboards

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by Dustin Sklavos

If you’re new here, welcome to the second part of my "How It Works" series. I’m going to be taking readers step by step through what’s inside their laptop and … how it works. This isn’t for geeks; I’m not going to try and confuse you or give you information you don’t really need or can’t understand. This is about getting the information you need to understand your laptop a little better, to know what to shop for online, or to be able to successfully shoo away the Best Buy employee trying to sell you a bunch of stuff you don’t need and prattling on about things he doesn’t understand. (Disclaimer: I used to work for Best Buy, and while some employees actually know what they’re talking about, I also worked under a supervisor who knew nothing about the hardware on the shelves.)

To get you on your way to making informed decisions, we have to make pitstops in places you may not be familiar with. Last week, I explained to you the basic terms that will help you understand how your laptop works. This week, I’m going to put them into practice and talk to you about motherboards.


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Motherboards

The function of the motherboard lies within the name of the part itself: it’s a board (specifically, a circuit board) and it’s the mother of everything in your computer – all connections have to go through it. Video hardware is plugged into it. The DVD drive is plugged into it. The scanner plugged into your USB hub? That hub is plugged into the motherboard.

Once you understand what the motherboard is, you begin to understand the difference between things like integrated and dedicated graphics. You understand how everything in your laptop is connected.

This gets a little tricky to navigate. If you look at a motherboard, you see a bunch of computer chips, a bunch of transistors and other electronic components. It’s basically like a silicon and copper pizza. And pizza is a good way to think about it. Great, actually, I’m proud of myself for thinking about that analogy. My folks would be proud.

So we start with a combination pizza. It’s got freaking everything on it. Pepperoni, sausage, peppers, olives, onions … this is the top layer, the toppings.

"Motherboard toppings" are basically the discrete video hardware, or the wireless networking, or the hard drive, or the DVD drive.

Your next layer is the cheese. It goes on after the sauce, but before the toppings. The RAM (memory) and processor are the cheese. In the same way you can’t get more basic than a cheese pizza, these parts are really the essentials that make the computer work.

Below that layer is the sauce. The sauce is vital to the pizza, and in this case, the sauce is the motherboard’s chipset. The chipset is basically the hardware that interconnects everything, and I’ll discuss this in greater detail later on.

Finally, you get down to the crust. The crust is what physically binds it all together, so the motherboard’s crust is going to be the board itself that holds everything.

So, with this blueprint in hand, let’s start at the top and work our way down.

Toppings: Peripherals

These are going to be covered in much greater detail later on in their own chapters, but suffice to say the peripherals include FireWire ports, the sound jacks and associated hardware, the wireless adaptor, the hard disk and DVD drive, and all the stuff you plug into the laptop.

Cheese: Memory and Processor

Again, these are going to be covered in greater detail in future entries, but you should be able to get by knowing that basically, these combine to form the brain of the computer. And like humans, some computers aren’t as quick as others.

Mercifully, unlike humans, computer memory can be easily increased. Humans will have to make do with reading regularly and doing crossword puzzles to try and improve our memory.

Sauce: Chipset

This is where we start getting into the nitty-gritty. It’s key to understand that like a network of roads and highways in a major city the chipset manages the interconnections within the computer. Another way to think of the chipset is like a translator at the Olympic games: in order to get everyone speaking the same language, they have to go through the chipset.

So we’re clear: Everything goes through this at some point. In fact, the only difference in recent years is that in AMD laptops, the processor interacts directly with the memory; in Intel machines, the memory goes through the chipset to the processor.

The chipset also defines what can be connected to the laptop (and specifically the motherboard). To be sure, the final decisions lie with the designers themselves who choose which connections they want to physically build and which ones they won’t. But the chipset defines what processors the notebook can use, what memory it can use, and how much of that memory it can use.

Now the reason it’s called a "chipset" instead of just a "chip" is because it generally involves two chips, called a northbridge and a southbridge, and "controllers" are typically split between these. USB, hard disk, and DVD drive controllers tend to be located in the southbridge, while memory controllers and oftentimes video hardware will be located in the northbridge.

So Dustin, you ask, why not just put all this crap in one chip? Well, it basically boils down to:

  1. Sometimes they do, but the chip may draw too much power or generate too much heat on its own since it needs to be much bigger to house all those controllers.
  2. Splitting the northbridge and southbridge can allow the notebook designer to "mix and match" parts depending on what the particular design needs. For example, there isn’t much point in installing a high-end southbridge that can couple multiple hard drives together if the notebook itself only has space for a single hard drive.

Generally, you aren’t going to have a whole lot of choice as to what chipset your notebook comes with and for the most part you shouldn’t care. For what it’s worth, here’s an easy way to figure out what chipset your computer has in case you’re curious:

  • If your notebook uses an Intel processor, it has an Intel chipset.
  • If your notebook uses an AMD processor and has ATI graphics, it probably has an AMD chipset.
  • If your notebook uses an AMD processor and has NVIDIA graphics, it probably has an NVIDIA chipset.

Crust: The Board Itself

The motherboard itself is what holds everything together, and on a desktop machine the individual "toppings" can be plugged into it pretty easily. On a notebook, more likely virtually everything is soldered in, but there are exceptions:

  • The processor is sometimes not soldered in, but replacing it would likely mean voiding your warranty and potentially just wrecking your laptop entirely. I’m pretty seasoned when it comes to laptops, but I wouldn’t dare try to replace the processor in my HP.
  • The memory is virtually never soldered in, and almost always comes with a convenient panel on the bottom of the notebook that lets you replace/upgrade it.
  • Wireless cards are oftentimes plugged into their own socket. For 99% of users, this isn’t important. It’s going to be user-accessible, but odds are you won’t be upgrading, and upgrades for these aren’t on the shelf in most stores.
  • The hard drive is almost always user replaceable, just like the memory, and will come with its own panel (and often tray) that can be removed.
  • In some notebooks (particularly Lenovo’s line), the DVD drive can be replaced/upgraded by the user. Notebook DVD drives typically need to be bought online, though.

I’ve given you a basic list of what’s inside your laptop that can be changed. Frankly, not a whole lot, so it’s important to buy right the first time.

Additional Stuff

Now, remember I said that the chipset can define what can be connected to your laptop, and occasionally that can involve some really cool stuff? For example, some modern AMD laptops can actually power down dedicated video hardware on the fly and switch to video hardware built right into the northbridge, thus saving power when running on the battery.

Some manufacturers also build flash memory right into the board to enable Vista’s ReadyBoost software, though this was rare to begin with and has become increasingly so given how inexpensive memory is.

Likewise, your chipset may also limit what kind of hard drive you can upgrade to, but there’ll be more on this later.

Conclusion

I’m hoping this entry felt a little less like a textbook. As before, I’ll condense the nonsense into news you can use:

  • Everything in your laptop is plugged into the motherboard.
  • The motherboard’s chipset mediates all the stuff plugged into the motherboard and allows it all to communicate.
  • Most consumer notebooks will allow you to upgrade/change the memory and hard drive.
  • The chipset will almost never be advertised because it’s not that exciting, but it’s good to know it’s there.

Coming Up: Processors

In next "How it Works" article, I’ll be tackling the processor itself, exactly what it does, and why a 2.2GHz dual core isn’t necessarily the same as a 4.4GHz single core.

Thanks for reading!


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