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Memory And Expansion Card Slots

How To Choose A Motherboard: A Guide For Beginners
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Memory technology support and configuration limits are normally thought to be tied to on-die controllers, but a motherboard's slot configuration can further limit your choices. For example, several microATX and smaller motherboards expose only two memory slots. Certainly, it's best to have at least four DIMM slots on a dual-channel motherboard or eight on a quad-channel platform, whenever the space for these slots exists.

All current motherboards support PCI Express 3.0 graphics cards (8 GT/s), though chipsets for AMD’s Socket AM3+ are limited to PCIe 2.0 transfer rates (5 GT/s). The transfer mode for platforms with CPU-based PCIe controllers is also limited by that component, so that putting a previous-generation Socket FM2 processor in a current-generation FM2+ motherboard will result in the slower transfer rate. Intel faced the same issue in its Sandy Bridge (PCIe 2.0) to Ivy Bridge (PCIe 3.0) transition two years ago, since both of those processors dropped intro the same interface.

PCIe x16, represented by the long slot in the image below, is primarily used for graphics cards. Thanks to standardization, it’s also compatible with non-graphics cards all the way down to PCIe x1. And it’s compatible with different generations, so that a PCIe 3.0 slot can host a PCIe 2.0 or 1.1 card without issue.

The two smaller slots in the above image correspond to PCI Express x8 and x4. They're suited for high-bandwidth devices like RAID controllers with eight or more drives and multi-connection GbE network cards. Notice also that they're open-ended. There's no plastic capping the back, which allows longer cards to fit in shorter slots if needed. Just remember that not all slots are open-ended. The feature is not well-documented, and you may need to look at photos of the actual product to determine if your longer card really fits into that shorter slot. And as long as you’re looking at pictures, you should also keep an eye out for other obstructions that could interfere with the use of an open end (such as the white heat sink pin, below).

The marketing force of CrossFire and SLI pushes motherboard manufacturers to put “graphics slots” in as many places as they can, even using physical x16 connectors wherever an enthusiast-class board has an electrical x4 or x8 link. As a result, x8-appearing connectors have become a rarity, even as x8 interfaces are incredibly common. The above motherboard also shows one example of a x8 slot that only appears to be x16; you can barely see the missing pins in the last slot.

Due to the limited number of pathways found on mid-priced platforms, many enthusiast-class motherboards can’t enable all of their slots simultaneously. This is a bad habit we try to call out whenever we see it. After all, it could be a huge hindrance to anyone with expansion plans for their whole board. It's most often a problem for the bottom faux-x16 slots of ATX-sized LGA 1150- and Socket AM2+-based motherboards, as well as earlier versions of those processor interfaces. These slots are usually wired to four lanes at most, sharing up to three lanes with x1 slots and/or on-board devices. Unless the manufacturer adds an expensive switch, slots or devices have to be disabled to make others operational. Because this is such a large problem for a few buyers, we list slot sharing in the Page 1 motherboard features table of our reviews. Motherboard manufacturers also list these limitations within the technical specifications sheet of each motherboard’s product page.

Added-in Controllers

Adding to the vast array of features controlled by the southbridge are third-party devices like secondary network, SATA/eSATA, USB 3.0 and/or IEEE 1394/FireWire controllers. Several factors have pushed these out of the mainstream and into smaller high-end markets, such as improved SATA features, an increased number of chipset-integrated USB 3.0 ports, and decreased popularity of FireWire devices. Add-in controllers usually employ PCIe x1 connections, using a logical "slot" where no room exists on the motherboard for a physical slot.

It may seem counter-intuitive to disable any device that increases motherboard cost, but doing so can reduce boot time. For example, the separate BIOS of unused add-in SATA controllers will often flash a "no drives found" error message just before the OS splash screen appears.

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  • 1 Hide
    olafgarten , October 1, 2014 3:47 AM
    I'd be careful with the size, sometimes cases with large CPU cutouts can't support mini itx motherboards
  • 1 Hide
    kamhagh , October 1, 2014 4:33 AM
    i hate psu on top cases :S looks ridicules !!!
  • 2 Hide
    MeteorsRaining , October 1, 2014 4:35 AM
    Great article, it has info on every small aspect that most mainstream users neglect, and the comparision b/w the chipsets and PCIe lanes support is very useful for first timers.

    The fact that memory clearance and slots often get overlooked, its better to have 4 slots for the sake of upgradility. Higher profile sticks often obstruct in cooler installation too.

    The chipset part was comprehensive, too. Well ATX form factor is standard nowadays, and given that most mid towers support that, I'd get it over mATX anyday, for more space b/w the components like GPUs.

    Also, higher the speed, lower the CL, better the sticks, but the fact that APUs require faster memory for optimal performance, because they use it as VRAM, should be considered. Faster memory helps in OCing too, timings don't matter as much, but yes it should not fall beyond CL11 for 2400MHz.
  • -2 Hide
    Novuake , October 1, 2014 5:36 AM
    Damn, I was busy creating a tutorial on this exact subject! Sigh...
  • 2 Hide
    Onus , October 1, 2014 6:01 AM
    Thomas, I think you got a little lost (though I wouldn't quite say "mired") in motherboard description rather than motherboard selection. You went into great detail on what is available, but very little on why someone might want or need it.
    I too have thought about writing on this subject. Novuake, by all means continue with your effort. More data points are almost always helpful, and we know that newbs sometimes need all the help they can get.
  • 2 Hide
    Crashman , October 1, 2014 6:07 AM
    Quote:
    Thomas, I think you got a little lost (though I wouldn't quite say "mired") in motherboard description rather than motherboard selection. You went into great detail on what is available, but very little on why someone might want or need it.
    I too have thought about writing on this subject. Novuake, by all means continue with your effort. More data points are almost always helpful, and we know that newbs sometimes need all the help they can get.

    Pick a CPU based on the apps you already use (on the PC you didn't build) and plan to use
    Pick cards and storage
    Pick the size of the PC you want. Make sure it's big enough for your cards and storage
    Pick a motherboard that fits those parameters.

    The rest is just, well, mostly reassurance :) 
  • 0 Hide
    Onus , October 1, 2014 8:15 AM
    Quote:

    Pick a CPU based on the apps you already use (on the PC you didn't build) and plan to use
    Pick cards and storage
    Pick the size of the PC you want. Make sure it's big enough for your cards and storage
    Pick a motherboard that fits those parameters.

    The rest is just, well, mostly reassurance :) 

    This is one reasonable synopsis of the process. What is then necessary is a discussion of slots, ports, and desired options for tweaking, particularly relating to performance (e.g. native vs. 3rd party controllers, VRM quality and BIOS options for overclocking, etc), size constraints, with component quality/longevity thrown in as well.

    What is needed is a crosstab table of chipsets and the features they support; e.g. RAID versions, USB3.0, SATA 6Gb/s, etc.

  • 0 Hide
    lp231 , October 1, 2014 8:29 AM
    How to pick a motherboard
    1. Decided on whether you want to go with AMD or Intel
    2. Pick a board based on the CPU you want to have
    3. Look at socket type, socket type must match the CPU you're getting, so if your getting a socket 1150 CPU, the motherboard must also say socket 1150. Same with AMD, AM3+ CPU must have a board that says AM3+
    4. Large cases can fit large boards and small boards. But small cases cannot fit large boards. Best to check out the case specs to see what boards will fit.
    5. If you want to run 2 video cards, make sure the board has at least 2x PCIe x16 slots. Those that support CFX and SLI will most likely have the CFX or SLI logo on the motherboard box. But check the motherboard manual or do some online research to confirm on it.
    6. Rest are just feature you want to have or not like wifi, Bluetooth, or the need for surround sound speakers. Most audio ports will just be Red, Green, Blue Some board will have that as well as Orange, Black, and Grey.
    7. Most important, out of all of them is not to rush on it. Do some research and read lots of reviews before buying.
  • 2 Hide
    Amdlova , October 1, 2014 9:28 AM
    Can be better this tutorial.
  • 0 Hide
    ta152h , October 1, 2014 11:20 AM
    One nitpick, AM1 is the platform for Kabini, not the socket. The socket is FS1b.

    The AM1 socket was a different beast. I'm still not sure why AMD chose this name a second time, with that in mind.
  • 0 Hide
    catatech , October 1, 2014 11:21 AM
    Maybe a comparison of audio chipsets(alc1150, 892,...), network chipsets(Realtek, Intel...), wireless chipses(2x2, 2x3,...), USB supported modes(xfast,...), PS/2 support, ... will also be helpful. Since those components count when a someone buy a motherboard.
  • 0 Hide
    ta152h , October 1, 2014 11:55 AM
    One thing I'd add is to pay attention to the maker of the motherboard.

    I bought an ECS only because it was the only motherboard that had what I wanted. Yes, I know, I still should not have, but I didn't know just how bad they are. It wouldn't use top of the line memory, wouldn't keep memory timings I put in, constantly lost the time, and had a terribly loud fan, on a processor that topped out at 25 watts. Then it started putting up the wrong display resolution, and wouldn't let me change it to the appropriate values for my monitor. I'd have to reset the firmware, then it would work, then fail again two days later. Pure junk.

    Technical support was abysmal as well. They solved nothing, and just kept asking me to do things I had already done, and told them I had already done. Entirely useless. I basically just removed the motherboard once the AM1 platform came out, since it was similar enough (I had an a6-5200, on the KBN-I).

    I'll never get another ECS. Even if the motherboard was a lemon, the fact they couldn't assist at all, and had one firmware release a few weeks after the first, and then nothing after that, makes it clear the company isn't very good.

    I replaced it with an Asrock, because I wanted DisplayPort (this is another important characteristic of a motherboard, make sure it has the video output that matches your monitor, if you have an existing one you wish to use with it), and no more problems.

    So getting a reputable brand is always a good idea.
  • 1 Hide
    lp231 , October 1, 2014 11:57 AM
    Those that comes to toms will want to know a lot of details, and are willing to learn. But for a beginner that dont know what thg is, just tell them what they must match. like amd cpu with amd board. The rest like raid, chipset, pcie lanes and whatever else comes in later on. Giving too much info in the first place just confuses them even more or drives them away from building their own pc as they think its way too complex, so they go and buy prebuilts.
  • 0 Hide
    Crashman , October 1, 2014 12:13 PM
    Quote:
    Those that comes to toms will want to know a lot of details, and are willing to learn. But for a beginner that dont know what thg is, just tell them what they must match. like amd cpu with amd board. The rest like raid, chipset, pcie lanes and whatever else comes in later on. Giving too much info in the first place just confuses them even more or drives them away from building their own pc as they think its way too complex, so they go and buy prebuilts.
    This is our second overhaul since 2006. We plan to release future revisions in more-frequent, smaller steps. And I'd personally like ideas on how to make it easier to read. I might even be able to take some stuff out, but probably not much. More important is probably to make sure all of the information is organized in an easily-read manner. Also, there might be a couple not-too-technical things I could add.

    So, I'm open to suggestions.

  • 1 Hide
    zakaron , October 1, 2014 12:52 PM
    I remember my first motherboard swap back in '97, I didn't take into consideration the peripherals I owned to match the connector type. I bought a socket 7 board to run a Cyrix P133+ that had an AT connector for the keyboard... well the Pentium 60 board I was replacing had dual PS/2 ports. I already had a serial mouse, but I was out of luck on the keyboard. I had to go back the next day to the computer show at the ExpoMart to track down an AT to PS/2 converter. Lesson learned: always make sure you have the correct hookups for the peripherals you want to use. IE: do you need PS/2, IDE for that old DVD drive, serial (for legacy device), floppy controller if you still use those ancient things, enough USB ports or do you need a USB hub, etc.
  • 0 Hide
    Onus , October 1, 2014 12:55 PM
    I think some feature comparison charts or tables could be helpful. Put socket/chipset on the vertical, and feature along the horizontal. My original suggestion ties to the chipset only, and what catatech listed would differentiate motherboards with the same base chipset by listing other distinguishing features.
  • 0 Hide
    Crashman , October 1, 2014 1:07 PM
    Quote:
    I remember my first motherboard swap back in '97, I didn't take into consideration the peripherals I owned to match the connector type. I bought a socket 7 board to run a Cyrix P133+ that had an AT connector for the keyboard... well the Pentium 60 board I was replacing had dual PS/2 ports. I already had a serial mouse, but I was out of luck on the keyboard. I had to go back the next day to the computer show at the ExpoMart to track down an AT to PS/2 converter. Lesson learned: always make sure you have the correct hookups for the peripherals you want to use. IE: do you need PS/2, IDE for that old DVD drive, serial (for legacy device), floppy controller if you still use those ancient things, enough USB ports or do you need a USB hub, etc.
    Ouch. That stuff was in the previous versions of the beginner's guide. I was hoping that people would have settled down to SATA and USB by now, just to circumvent your issues, because they make the discussion a little boring and hard to follow.

  • 0 Hide
    kittle , October 1, 2014 1:22 PM
    Quote:
    This is our second overhaul since 2006. We plan to release future revisions in more-frequent, smaller steps. And I'd personally like ideas on how to make it easier to read. I might even be able to take some stuff out, but probably not much. More important is probably to make sure all of the information is organized in an easily-read manner. Also, there might be a couple not-too-technical things I could add.

    So, I'm open to suggestions.

    So... some suggestions

    Since this article is supposed to be for beginners:
    AMD vs Intel -- Need to pick one. why? Pros and cons for both
    CPU - Speed, # of cores, hyperthreading. whats good, whats not.. and why? (leave out any overclocking discussions)
    RAM - how much? .. what kind? and why?
    What chipset do I need/want. And why?

    -- note that each point has a "why" component. You seem to have left that out of your article.

    (Im leaving out PSU, HDD and GPU)


    As noted by @ta152h - the manufacturer of the motherboard matters a lot. Some companies make better boards on average that others. but as with everything there are compromises.. Better companies usually charge more.

    next a "how-to" section
    - how to make sure the CPU will even FIT the motherboard
    - how to make sure the CPU is compatible
    - how to pick the right RAM (focus on mainstream compatibility, not overclocking)
    - how to make sure the board will fit in my case (or how to pick a case for my motherboard)
    - how to pick a good motherboard manufacturer


    Lastly - since picking a motherboard usually means the person is building a new system, some basic recommendations would be helpful.
    Office/Kitchen system -- no gaming, or VERY light gaming
    - lower cost
    - high reliability (it wont be replaced anytime soon)
    - no overclocking
    - onboard graphics (or cheap gpu)
    - single HDD: 500gb/1TB HD,
    - 4GB ram
    - 300-400w PSU

    Gaming oriented system
    - mid to higher cost
    - dedicated GPU (single, no SLI)
    - overclocking available, but this is not a beginner subject
    - SSD boot drive & mechanical storage drive (2TB+)
    - 8GB ram or more
    - 650w PSU

    Anything beyond that.. and the person in question is not a beginner, so the article does not apply.
  • 0 Hide
    Crashman , October 1, 2014 1:41 PM
    Quote:
    Quote:
    This is our second overhaul since 2006. We plan to release future revisions in more-frequent, smaller steps. And I'd personally like ideas on how to make it easier to read. I might even be able to take some stuff out, but probably not much. More important is probably to make sure all of the information is organized in an easily-read manner. Also, there might be a couple not-too-technical things I could add.

    So, I'm open to suggestions.

    So... some suggestions

    Since this article is supposed to be for beginners:
    AMD vs Intel -- Need to pick one. why? Pros and cons for both
    CPU - Speed, # of cores, hyperthreading. whats good, whats not.. and why? (leave out any overclocking discussions)
    RAM - how much? .. what kind? and why?
    What chipset do I need/want. And why?

    -- note that each point has a "why" component. You seem to have left that out of your article.

    (Im leaving out PSU, HDD and GPU)


    As noted by @ta152h - the manufacturer of the motherboard matters a lot. Some companies make better boards on average that others. but as with everything there are compromises.. Better companies usually charge more.

    next a "how-to" section
    - how to make sure the CPU will even FIT the motherboard
    - how to make sure the CPU is compatible
    - how to pick the right RAM (focus on mainstream compatibility, not overclocking)
    - how to make sure the board will fit in my case (or how to pick a case for my motherboard)
    - how to pick a good motherboard manufacturer


    Lastly - since picking a motherboard usually means the person is building a new system, some basic recommendations would be helpful.
    Office/Kitchen system -- no gaming, or VERY light gaming
    - lower cost
    - high reliability (it wont be replaced anytime soon)
    - no overclocking
    - onboard graphics (or cheap gpu)
    - single HDD: 500gb/1TB HD,
    - 4GB ram
    - 300-400w PSU

    Gaming oriented system
    - mid to higher cost
    - dedicated GPU (single, no SLI)
    - overclocking available, but this is not a beginner subject
    - SSD boot drive & mechanical storage drive (2TB+)
    - 8GB ram or more
    - 650w PSU

    Anything beyond that.. and the person in question is not a beginner, so the article does not apply.


    I see what you're saying, but what I think you're really asking for are a CPU guide for beginners, a DRAM guide for beginners, a storage guide for beginners, and more "about you" stuff in the "how to build a computer" guide.

    That last thing, maybe an introductory article like "Beginner's Guide To Beginner's Guides: PC Tech 099"
  • 0 Hide
    Amdlova , October 1, 2014 1:51 PM
    No mention of power suppy. Crap sound. the only reason i get 130 us plus motherboards is because the sound some mother boards have snr 90 db.
    I don't care if the mother board will fly some high party lan or other things. I never used the ie 1394 plus E-sata...
    for now i got only asrock motherboards because sound nice with my edifier and my akg headphone.
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