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How to Pick the Right Motherboard for Your Custom-Built PC

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Motherboards are the most complex component in your computer. Fitted with hundreds of components and dozens of options it can be difficult to choose. Let’s look at the most important factors to help you decide before building your next computer.

Motherboards are the central nervous system of your computer. They are responsible for connecting and communicating between all of the important components inside. Knowing what to look for is key when comparing boards.

Motherboard Sizes

Motherboards come in different shapes and sizes, but luckily there are some standards set in place so that a lot of motherboards and cases can work together.

For the most part these sizes apply to all desktop computers but some computers you buy from manufacturers don’t follow all the rules. This is usually fine when you buy the whole computer as a unit, but it becomes tricky if you want to swap a new motherboard into the case or build one from scratch.

The most common motherboard size is Intel’s Advanced Technology Extended (ATX) and its derivatives. The chart below has some of the most common ATX sizes, but there are plenty more options than just the few shown here.

Motherboard sizes not only indicate the size of the board and placement of mounting screws, but it also dictates the general layout of the major components on the board. Have you ever noticed that almost all motherboards have the CPU, RAM, and I/O ports in the same place? That is because they are determined by the board standard. The components have to be in the same place otherwise case and power supply manufacturers wouldn’t easily be able to sell you something that works with with your motherboard no matter who makes it.

For ATX motherboards the general layout of the board is shown in the picture below.

Intel’s second attempt at standardizing motherboards was with Balanced Technology Extended (BTX). The main focus of BTX was to solve airflow and component placement limitations of ATX. Although BTX was supposed to be the successor to the ATX form factor, it didn’t gain enough traction to take off in the consumer market. Some large computer manufacturers such as HP, Dell, and Apple still use BTX, or proprietary variations of it. The main layout differences can be seen in the picture below.

Because BTX has been abandoned by Intel since 2007, you will just need to focus on which ATX size best suits your needs. Typically the main difference between small ATX boards and larger boards are expansion slots and CPU support.

Processor Sockets

Image via kwixson

The processor socket you choose is the deciding factor in what CPU you can use in your computer. If the processor doesn’t fit, you can’t use it. Intel and AMD both have their own series of processors and sockets that are compatible with only their chips. The first thing you will need to decide is which processor you want and then you can decide further on which socket you need.

Intel’s sockets usually have a friendly name, like Socket H, and a technical name like LGA 1156. The friendly name is easier to remember while the technical name will tell you about the socket. LGA 1156, for example, stands for Land Grid Array and it has 1156 pins. Because CPUs and motherboards change so often it probably isn’t worth it to describe what processors work in which sockets. Instead you can get that information on which CPU series work with which motherboards from your manufacturer.

For Intel’s consumer sockets they typically have a low power, e.g. Socket 441 for Atom processors, a midrange, e.g. Socket H for Celeron, Core i3, Core i5, and Core i7 800 series processors, and a high end, e.g. Socket B for Core i7 900 series processors. If you are looking to use an Intel processor you will need to find which socket supports the processor you want.

AMD hasn’t been changing quite as frequently as Intel and in the past 5 years they have only had 3 major consumer sockets. The AM2, AM2+, and AM3 sockets support almost all of AMD’s consumer processors currently. The AM2 and AM2+ were mostly interchangeable and the AM3 was introduced to support DDR3 memory.

In either case, it is a good idea to pick your processor first, and your motherboard second. If you buy a socket with no processor support, it isn’t going to do you much good.

Chipsets

Image via adikos

The chipset is how your CPU, RAM, video card, and peripherals communicate. It is a combination of your northbridge and southbridge and can add some very nice features depending on your needs.

The northbridge is typically responsible for the very fast communication between your CPU, RAM, and video card. It is where you will get features like SLI/CrossFire and DDR3. With the current Intel and AMD processors the northbridge functions are all included in the processor. This means less complexity for your motherboard and typically less latency for the processor to access the high speed components like RAM.

Integration is great news for performance but sometimes bad news for options. For instance, because AMD owns ATI they could have the ability to lock their latest gaming graphics cards to only having specific features if you are using an AMD processor. This also put companies like Nvidia out of the northbridge market who use to make one of the best northbridge chips back in the Pentium 4 processor days.

The southbridge will give you features like support for the latest PCI-E, SATA, USB 3, and many more future technologies. It is also essential to know what options you need because some southbridges may not support every feature you might expect like RAID and surround sound. With most manufacturers they will clearly state the features available without needing to dive deep into the southbridge chipset features.

Because this combination of features + processors + options is so big and changes multiple times per year it would be impossible for us to list every option here. Instead, just be aware when you are picking your motherboard of what features you need and then look for those options in your boards chipset.

Other options

A lot of manufacturers will try to sell you on a motherboard based on extra features like the amount of on board I/O ports, amount of expansion slots, or the reliability of their motherboards. These can all be requirements depending on the purpose of the computer you are building. Once you figure out the processor and size of motherboard you want, these added features will probably become the next most important thing, especially with smaller form factor motherboards when space is limited.

It is typically easier to use onboard features if they are available than try and expand the computer to have all of the options you need. If you know you are going to need two network cards or HDMI with audio pass-through, make sure your motherboard supports it before buying.

The manufacture’s description may not be 100% clear on if the feature is supported or not. Other places to look for clarification on specific features are device reviews, forums, and wikipedia. You may also want to download the PDF user guide for the motherboard just to see if it is documented on how to enable the features you need.

If you have clear decision for what you need in each category you can quickly narrow down the endless sea of options available. This can greatly ease the stress when trying to decide on a motherboard just by price or maximum memory supported.

Justin is a Linux and HTPC enthusiast who loves to try new projects. He isn't scared of bricking a cell phone in the name of freedom.

  • Published 05/11/11

Comments (40)

  1. C12ASH13

    Very interesting article, I hope to see more like it!

  2. jim

    spot on with all your info. nice job. can refer this to people who ask me about picking a proper mobo. hate having to explain a lot of this in dumbed down terms ;)

  3. Bruce Connor

    What should I look for in a mb if I know I’ll be using the Pc with a home teather set? Is an extra pci slot for the soundcard enough?

  4. Robin K.

    Well-written and informative for novices. Small typo though: “land griD array”.

  5. JMC

    Good article indeed… Can I know what motherboard is in the first picture on top?

  6. Jithin

    Hey just look at the first pic… it has 2 processor sockets and 12 DIMM slots…

  7. durr

    Northbridge doesn’t exist anymore since it’s integrated in todays CPUs. And you forgot CEB-boards

  8. Gene

    The mother board is EVGA Classified SR-2 270-WS-W555-A2 LGA 1366 Intel 5520 SATA 6Gb/s USB 3.0 HPTX Intel

  9. Hatryst

    This article should be a part of HTG’s “How to Build Your Own PC” series. Really good.

  10. bobro

    nice article, please can we get one on ITX boards next :D

  11. david

    @Bruce Connor. Most boards now a days support home theater setup. Just check to see if it has at least one of 3 options: HDMI, Toslink (optical), or Coaxial Digital (usually colored orange or black and looks like RCA port).

  12. Mike

    That’s a pretty sturdy looking mobo in the first picture. Damn. Thanx.

  13. Roger Wilco

    This article just makes you hungry for more information. There are so many features on a MB that should be considered even if you already bought a processor first.

  14. Andrew Diamond

    Any suggestions on boards that support Linux?

  15. Paul

    Great article – very informative and lays enough groundwork that newbies can go and find out more information for themselves. Thanks!

  16. Cirric

    I build PCs to get the best processor performance, at least double, of the PC I broke. AMD 1600+, then AMD 3200, then AMD Phenom Black dual core at 3.2gHz. Once you know which processor you will use just find the best compatible motherboard you can afford. The one I have now has a conductive layer of twice the thickness of a standard board. I’m afraid that it runs so cool and fast that it will outlive me!

  17. R Baig

    Hi,

    interesting article about mother board,

    Can u do more in the favour

    Give us the brief about Work station and server boards and also about working

  18. Larry

    Its not to complicated building one, just do your home work searching reviews at a site like Newegg.com which shows the layouts of the boards ..Then the pdf user guide of motherboard at the manufactures site. ..My opinion having a stable computer is more important than having the most speed and choosing a top manufacture like Asus or Gigabyte u r less likely to go wrong..U want to check the pdf layout at motherboard manufacture to see which Processors and Ram are supported..If u get Ram that isnt supported u could have a unstable computer and unhappy..Also go with quality Ram such as Corsair, Mushkin, Crucial and G Skill, not cheap off brand stuff..For most the onboard audio is fine but i recommend buying a quality video card instead of using onboard video, especially if using it for a gaming system..Buy a quality ATX case and power supply Like Corsair and then u dont have to worry bout MB size as much later if doing another rebuild…OOps dont believe they were talkin bout building a puter but hope this was helpful for 1st time builders..

  19. Phil

    I’d mention backwards compatibility as an important factor for some people. Granted I don’t use ISA slots anymore, but I do like to find motherboards which are compatible with PS2 mouse/keyboard, parallel and serial ports, and even floppy drives. I don’t think I’ll need to use most of that stuff anymore, but it’s nice to know that I can – if it becomes necessary sometime in the future.

  20. Steven Shaffer

    I would like to like to add to your idea of picking a motherboard. If you are an avid overclocker like myself please oh please, don’t purchase a $70 motherboard and then question why your friends $250 motherboard overclocks so much better. When it comes to overclocking it is simple. Find your favorite brand, find the socket for the chip you want to use, and purchase the most expensive board you can afford. Then get a power supply from any reputable manufacturer. You’ll find out later that the overclock will come so much easier with the better bios, and electronics in the more expensive motherboard will be more stable. Now obviously that’s not all that there is too it. Read up on the chip you want to buy and look and see what others have done with it. Reference sites like Overclockers.net (my favorite), Tom’s Hardware and others, and you’ll be off to a really good start

  21. expat53

    I thought the article would be more informative. It was ok, for a brief overview.

  22. ProstheticHead

    @Mike, “That’s a pretty sturdy looking mobo in the first picture.”

    I like that, you’re a legend lol.

  23. wayne small

    what type of motherboard did gateway use in their 450 series and what mother board is equivalent to it

  24. Richard Ayres

    THe physical dimensions of the standard MoBs would be useful or am I missing something?

  25. drecked

    Good one Larry , Your comment is more informative than the article !

  26. KsGeek

    Check Wiki for “Computer form factor” they have a really good chart with physical dimensions.

  27. Amanda

    the northbridge still exists, what u have today is a frontside and backside bus in the cpu, also when it comes to say hdmi then u need to look at a graphic card as the onboard graphics are generally limited ,if you want a good pc then u need a good graphic card as especially today web sites os’s etc are very graphical if u run vista up u get a windows experience level and the main thing that rates it down is the graphic card, also u need ram of 4 GB as 32 bit os’s only address that amount of RAM, however if u have a 64bit OS then u can utilise more ram, also if u are into virtual pc’s u can specify how much ram that pc will use

  28. Amanda

    my question is Gigabit or ASUS what do u think is best as I have a custom built PC to sell

  29. Amanda

    Corsair RAM is good it comes with its own heatsink, also when u are looking at motherboards etc u need to make sure it supports the CPU the amount of RAM and OS and number of HDDs u wish to use. A good power supply is also important as it runs everything, and a good cooling system (Fans or a passive cooling system)
    Also make sure it has at least one PCI-E slot as AGP is out

  30. rick

    You dont need to spend a whole heap of cash building competetive gaming decks. I built mine for under $600.00 Shop around. if you are in perth west aus, by far the best prices are found at netplus computers in ossie park (n i dont work for them!) I have found that a single MSZI gtx460 1Gb on g41mt-es2l mboard with quadcore intel processor and 8Gb ram is very capable for gaming whilst being very cost effective.

  31. Ed

    What motherboard did gateway use in their SX2840-0?
    The processor is Intel Core i3 530.

  32. Jaack

    Article mentioned 1156 socket but didn’t see 2nd generation LGA1155 boards. Maybe I missed something but 2nd gen chips not mentioned at all like core i5-2500K/ core i7-2600K Now mention of 22nm fab coming within 6 to 9 months means new chips with another incompatible MB CPU socket?

    Will LINUX be able to keep up with the newest hardware if Intel and C/Set mfgr are Microsft centric but not open source.What about PCI-e x16 x8 X4 X1 slots.Needs an explaination somewhere.
    Intel or AMD? What best CPU chip/MB mfgr ,Video card(s) model & mfgr. MSI Gigabyte ASUS who make the best MB or video card. Then case PS and memory.+1 SSD drive for boot etc. Can do for under $1000

  33. Albatroscem

    Thank you for this I found it interesting and very helpful

  34. Aurule

    @Andrew Diamond: pretty every mobo on the market can run linux. If you’re looking for something that supports an OSS bios (i.e. coreboot), take a look at their support list: http://www.coreboot.org/Supported_Motherboards

  35. Hillal

    Very gud Info,

  36. Shado

    On point indeed, learned a lot about bridges especially. Good Job!

  37. JimB

    I’d approach the ‘what motherboard’ decision from the point of view of:
    What is your system to do –
    Portability required, Cooling needs – airflow available, standby power usage if ‘always on’
    Gaming, HD video, Office work, bulk data store
    That should guide you to a CPU type for the power usage and power per core, memory and 32/64 bit

    Then there is the video card and external device connections – multi-monitor, high-resolution and fast response, large screen, 50″ HDTV (hdmi) home-theatre, and eSATA/USB devices – possibly via an add-in board.
    Remember the video memory comes out of your max addressable memory space (4GB under Win32)
    A 2GB video system has a seriously debilitating effect on the available memory for applications & games – then again will your favourite game, and selected video board give slower throughput if allowed more than 2GB of memory space – Toms Hardware again.)

    So how many ‘channels’ for each of that ‘lot’

    Going to use RAID for speed, or for recoverability (yes – you’ll want it in hardware, not software)
    Check that the motherboard can handle all required devices doing concurrent transfers

    Back to shelving, PSU, UPS, and cooling needs – perhaps reconsidering the case design – wireless via front USB slots – especially if the case is to be ‘built-in’ to furniture, and consequently have limited access to the rear, and restricted airflow.

    Perhaps reconsider the CPU housing – water cooled

    I usually reccomend a mid-range motherboard and CPU, with the saved cash spent on better video, storage access paths and CPU stress relieving

    No point in having a system with a CPU that is idle for 60% of the time waiting for the next block of data to be input from the drive

    Many PCI/PATA based systems had DVD and hard drive sharing an interface cable – a fiver for a new cable and they each get their own cable, so you can have concurrent actions from the DVD and the hard drive (activities such as teh pagefile).

    Extra memory, (and a 64 bit OS) and the system may not need to use the hard drive for a pagefile – throughput increase – maybe 10% overall, and possibly more than 30% at times of heavy loading.

    Extra hard drive, with your main software on it, and you’ve split the OS loading on the drive, probably a 10% increase in throughput.

    (SSD with the software on it so it’s mostly a read device and, except for a pure gaming system, that’s probably going to do more for throughput than overclocking by 30%)

    Double the size of the hard drive, and only use the low address half for the normal ‘work’ and that’s probably 10%, or maybe 20% better throughput – review drive performance as the activity moves across the drive surface at sites such as ‘TomsHardware’

    You can always use the ‘high address’ part of the drive for DVD images and backup images – data store where the system is not making hard use of the drive, or for times when you are not annoyed by the intermittant slower response.

  38. LOST

    Thanks a lot … That’s was Helpful For noob like me .. :D

  39. BB

    Great article, thanks!

    Suggestion for another article — on memory, and in particular backwards-compatibility i.e. using newer memory in older machines.

  40. Next Day PC has Todays Computers and Electronics for everyday

    You’ve got great insights about Next Day PC Todays Computers and Electronics, keep up the good work!

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