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Step 12: Install Cables, Cards, And Drives

How To Build A PC: From Component Selection To Installation
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Expansion cards are usually available as PCI Express (PCIe), since legacy PCI is nearly extinct. Available in single-, four-, eight-, and sixteen-lane versions, the PCIe standard retains compatibility between shorter cards and longer slots. The below image shows a PCIe x1, PCIe x16, and PCI slot for comparison.

PCIe allows shorter cards to be placed in longer slots, such as an x1 card in an x16 slot. Conversely, longer cards can only be placed into shorter slots when the forward end of that slot has no cap. Because the difference between open-ended and closed slots isn’t easily seen in photos or explained on motherboard specification sheets, many manufacturers use x16 slot connectors for their four- and eight-lane interfaces. If you noticed that half of the electrical contacts are missing from the above PCIe x16 slot (the little metal pieces are tough to see), it’s because that slot is wired as an x8 interface.

Though our example motherboard includes on-board graphics, we chose to use a PCI Express graphics card for enhanced performance. The PCIe x16 card is inserted until a latch on the slot engages the card's hook. These latches are present on most PCI Express x16 slots, but are not found on lower-bandwidth PCI and PCI Express x1 interfaces.

As with other cards, a case screw or quick-release latch secures the top of the card's metal bracket at the opposite end.

Internal 3.5" drives are traditionally secured with coarse threaded (UNC) case screws, while external drives, 2.5" drives and bay devices usually have fine metric threads. External drives typically slide in from the front, while internal drives often slide in from inside the case.

Several manufacturers offer tool-free installation using drive rails, sliding latches, or other pin-loaded devices that engage with screw holes. Our case reviews highlight several designs.

The motherboard cables of new systems are usually based on the expanded EPS12V standard, which encompasses previous ATX standards. Previously found on server-sized EPS power supplies, the 24-pin main power cable is both forwards and backwards compatible with the earlier 20-pin part. The below example shows how a 20-pin plug fits into a 24-pin socket; the wide latch is designed to work with either 20-pin or 24-pin plugs.

One of the reasons for a 24-pin power cable includes added amperage supplied to PCI Express slots compared to older interface standards. While most cards won't overdraw a 20-pin connector, graphics card makers occasionally have suggestions for a higher minimum level of available power.

The 4-pin or 8-pin ATX 12V connector satisfies the electrical demands of the CPU. Formerly known as the "P4" power connector, it was added by Intel to supplement its Pentium 4 processors, and later adapted by AMD motherboard designers. The newer 8-pin versions were originally meant to address phenomenally power-hungry Pentium D and Prescott-based Pentium 4s, but many modern AMD and Intel processors are efficient enough to once again work from 4 pins. Most 8-pin boards will work with both 8-pin and 4-pin power, as the connectors are cross-compatible.

Also seen in the photo above is a 4-pin CPU fan power connector and the front-panel audio connector. On-board 4-pin fan connectors are designed to provide pulse width modulation (PWM) automatic speed control, but the connectors are once again cross-compatible with 3-pin fans. Some motherboards are able to control fan speed via either voltage changes or pulse width, while others will run the “wrong” fan at full speed, continuously, without harming the system.

Front panel audio cables are often available with both AC97 and HD-Audio connectors, where HD-Audio is a slightly newer standards and AC97 is extinct. Using the "wrong" connector may temporarily reduce the number of available audio channels, but will not harm any components. The key-pin for audio headers is in a different location from other panel connectors to ease installation.

The case's power switch, power indicator light, reset switch, and hard drive activity light are usually connected at the motherboard's lower-front corner. LEDs pass current in only one direction, and positive pins (indicated by a "plus" sign below) normally connect to the colored wire on each lead. A black or white lead wire usually indicates negative or ground state. If your power and reset switches work but your power and HDD lights don't, your LED connectors are probably flipped.

USB connectors have been standardized for over fifteen years, and we suggest that first-time builders not attempt to incorporate any parts older than that. The missing pin location is blocked by most front-panel USB connectors to assure that the connector is polarized correctly. A reversed connection would damage the motherboard, so 4-pin, 8-pin, or single-row internal break-out cables require special care. The missing pin indicates the negative/ground end of the connector.

Device Cable Installation

Serial ATA (SATA) power and data cables are keyed on the sides, as seen on the drive below. Some early SATA drives were also able to accept older 4-pin ATA power connectors. The sticker warns that builders should choose either SATA or legacy power, but not both.

Many PCI Express graphics cards require more power than the slot is able to provide, and use the 6-pin input connector shown below or a newer, higher-amperage 8-pin version. The 6-pin connector must never be confused with 4-pin or 8-pin motherboard power, as its polarity is the opposite of those! Fortunately, the newer 8-pin PCI Express power cables are designed in such a way that they cannot be forced unintentionally into a motherboard’s 8-pin connector.

Are you trying to rescue data from an outdated drive on your new system? New motherboards don’t support these drives natively, old SATA-to-ATA converters often had limited compatibility, and old drive interface cards used legacy PCI. If you really are stuck trying to pull childhood photos off a deceased family PC, I’d like to suggest installing the drive in an external USB-based adapter. That is, if you can still find one.

ATAPI and Ultra ATA drives have pin 1 on the "other" side of the connector, as seen when facing it (on the right in the photo below). A key is located on the top of all 80-conductor ATA cables to prevent upside-down insertion.

Final Words

No system is complete without software, and most operating systems are available on a bootable DVD. The system's boot order can be selected in the motherboard BIOS, usually under the "Advanced BIOS Features" menu, and should be set to boot from CD first. Many modern motherboards will list the actual name of the drive in the boot order, while others will only list it by device type.

Further BIOS tips and tricks can be found in our BIOS for Beginners.

We hope that this series has made your build a complete success, but if it hasn't, members of our Community Forums eagerly anticipate your technical questions.

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  • 6 Hide
    gofasterstripes , June 23, 2014 2:11 AM
    Can I once-again say a big "Thanks" to the Tom's team for writing a great article which will save me lots of time and hassle in explaining PC building and component selection to n00bs who ask me for help.

    Cheers!
  • -1 Hide
    JOSHSKORN , June 23, 2014 2:57 AM
    What about NUCs and cases alike? Yes, I realize those are too small for discrete GPU cards, but depending on your usage and space, it just might be what one needs.
  • 4 Hide
    Crashman , June 23, 2014 3:06 AM
    Quote:
    What about NUCs and cases alike? Yes, I realize those are too small for discrete GPU cards, but depending on your usage and space, it just might be what one needs.
    It's addressed in the last two sentences of page 1:
    Quote:
    Intel even jumped on the tiny bandwagon with its similar-appearing NUC (Next Unit [of] Computing) form factor. Most of these machines are available either as a barebones system (no drives or memory) or a complete PC, and all of them use external, notebook-style power adapters.
    There's really nothing more to say. You don't build these from separate components, you just finish them with a drive and memory as you would any of the other systems covered in this article.
    Quote:
    Can I once-again say a big "Thanks" to the Tom's team for writing a great article which will save me lots of time and hassle in explaining PC building and component selection to n00bs who ask me for help.

    Cheers!
    You're welcome!
  • -1 Hide
    revanchrist , June 23, 2014 3:25 AM
    Should put in a Cooler Master Elite 110 to showcase a mini-ITX instead of that huge Lian-Li.
  • 1 Hide
    illuminatuz , June 23, 2014 3:47 AM
    Guess most of the issues in the forums will be ironed out by this one simple post..
    Wonderful as usual toms.. Appreciate it..
    :D 
  • 1 Hide
    rolli59 , June 23, 2014 5:46 AM
    Most if not all issues brought up on the forums have answers in some or the other article on Tomshardware. This article compiles answers to build questions.
  • 1 Hide
    AMD Radeon , June 23, 2014 6:37 AM
    This article is very good reference newbies asking how to build PC in toms forum.
  • 0 Hide
    DookieDraws , June 23, 2014 6:54 AM
    Long time reader of Tom's Hardware, even before I finally became a member. This has been a very helpful site to me and my friends over the years. In fact, this IS our go-to site for when we need to figure something out. I am always learning something new.

    Great article! No doubt this is going to help a lot of folks.

    Thanks, guys!
  • 1 Hide
    Yuka , June 23, 2014 7:25 AM
    Very good write up guys.

    I think you missed a section for "SLI - XFire", but it's great overall. Since its a guide for folks with little to no knowledge, I think it would help them to dispel myths and get some facts over XFire and SLI.

    Cheers!
  • 2 Hide
    Xeres Forteen , June 23, 2014 7:53 AM
    Good article with excellent info. I'm going to just add my 2 cents on how I like to do the actual assembly of the PC after receiving the parts.

    First I put the motherboard into the PC (not fastened) to see where the standoffs are going to be placed onto the case. Also I note what routes I'm going use for my cabling. Then I take the motherboard out and insert the standoffs and port plate into the case. Also I take my case cables (power sw, reset sw, USB, front audio and mic cables and put a twist tie around them all and place them near where they are to be plugged into the motherboard. These cables are easy to lose track of.

    Next I place the power supply, and "bay devices" (optical drives, non-removable storage, etc) into the case and have those cables attached and either hanging over the outside of the case or routed behind the motherboard tray. This obviously depends on how you determined the cables will be routed earlier.

    Then I take my motherboard, put the CPU, RAM, and cooling system on as much as I can. Then I place the whole thing into the case - usually at an angle at first, leading with the side with the RAM (which is normally going behind the case bays in smaller cases) in first.

    At this point it's just a matter of aligning the motherboard with the standoffs and port plate. Plug it all in (including the case plugs which are conveniently out of the way and together).

    Power it all on and volia!
  • 1 Hide
    Onus , June 23, 2014 8:03 AM
    I would like to have seen the article begin well before case selection, with questions as to purpose for the build. Define the purpose, then you know what sort of parts you'll need for it. The case is often the last component I choose, and only once was the first, when the purpose was to build the smallest system possible that would meet my needs.
    Otherwise, it was a good article. People who are uncertain of building their own PCs can learn a lot from it.
  • 0 Hide
    zelgar , June 23, 2014 9:10 AM
    I'm a little confused with the section dealing with Choosing your Power Supply. If the power requirements of the components is 647 W as shown in the example, how could you use any power supply that isn't designed to higher wattage? Is it expected that only 85% of the design load will ever be used (i.e., that you wouln't be using the max energy requirements of all of your components at the same time)? Wouldn't it be better to have your power supply based upon the max usage of the components since this may occur (e.g., running a modern game at max settings that your computer can run)? Aren't Power supplies rated Bronze/Silver/Gold/Platnium at 80% of the Power Supplies capacity, so you'd want a PS that is would be running at 80%+ at max load (e.g., 647/.80 = 809 W or 647/.85 = 761W)?
  • 1 Hide
    Damn_Rookie , June 23, 2014 11:35 AM
    Quote:
    I'm a little confused with the section dealing with Choosing your Power Supply. If the power requirements of the components is 647 W as shown in the example, how could you use any power supply that isn't designed to higher wattage? Is it expected that only 85% of the design load will ever be used (i.e., that you wouln't be using the max energy requirements of all of your components at the same time)? Wouldn't it be better to have your power supply based upon the max usage of the components since this may occur (e.g., running a modern game at max settings that your computer can run)? Aren't Power supplies rated Bronze/Silver/Gold/Platnium at 80% of the Power Supplies capacity, so you'd want a PS that is would be running at 80%+ at max load (e.g., 647/.80 = 809 W or 647/.85 = 761W)?

    The 647W is measured at the wall socket, as the article mentions input power. After taking into account the 85% efficiency of their power supply in this example, the PSU is only outputting 549.95W to the PC components at max load. Adding some headroom they come to the 600W PSU recommendation.

    Personally I'd like a little more headroom, but the calculations in the article are correct.
  • -1 Hide
    zelgar , June 23, 2014 12:00 PM
    I think the article will confuse noobs of talking about the power measurement at the wall socket versus the power rating of the power supply. If the sum of the power requirements of the computer components is X, they need a power supply the provides more than X. Making them aware that the power supply will be using more energy than X at the wall is useful to know so that people don't buy a PSU that is too wasteful. Since undersizing a PSU is more catestropic than oversizing one (e.g., crashes/boot faiolures vs electricity costs) getting one that meets the needs of the components is the starting point of evaluating PSU.
  • -1 Hide
    n3cw4rr10r , June 23, 2014 12:37 PM
    I usually buy my pc components from Amazon. #1 customer service. They dont give you any bs. Hell they even send you a pre-paid shipping label to ship the item back. I have never had they charge me a "re-stocking" fee on any item, even when I returned item because I did not like it.
  • 0 Hide
    PapaCrazy , June 23, 2014 1:16 PM
    After all this time, why do I still get the most excited about the cases? Maybe cuz the components are logical forgone conclusions, but the case is the artistic, subjective bit? I don't know, years at this stuff and a sexy case still turns my head. The mobos are starting to look really sexy nowadays too.
  • -1 Hide
    Jim Maher , June 23, 2014 3:03 PM
    Great article! This is a wonderful overview, and should prompt most readers to research their more detailed questions on the forums.

    Building your own is great fun, and most serious users should probably give it a try at least once in their lives. Given that, I'd recommend an annual "refresh" of this article, with updated info and re-validated links to corresponding reference articles and resource forums.

    A great service to your readers!
  • -1 Hide
    chaz_music , June 23, 2014 5:24 PM
    Excellent article with lots of interesting information.

    I wanted to comment on the power supply part of the article. One is the efficiency and the total cost to use versus the front end purchase cost. A less efficient system will obviously create more total heat as wasted energy. But aside from possibly making someones room rather uncomfortable, it also increases your airconditioning energy use. A good rule of thumb is that an AC system will use 50% of the heat energy. To add the total annual cost, multiply that times the percentage of the year that the AC is on. So your example of a 647W system with 85% PSU would give (550W used):

    647W - 550W = 93W at plug

    93W * 50% = 47W AC energy

    Total Energy (summertime) = 93W + 47W = 140W

    If the AC were on the while year and the PC were on continuously, this is about $140 annually, or almost $12 per month added electricity in the summer. If you did the same thing with a cheap 70% efficient system, you get $248 annual cost which is $20.63 per month summertime cost. At a difference of $8, it does not take many months (of continuous on!) to make the more efficient PSU make much more sense.

    The other topic I wanted to comment on is ESD. I am an engineer and work with ESD issues everyday. It is a very real an poorly understood issue by many because of the often hidden or delayed failures that it causes. ESD many time causes walking wounded damage without an immediate failure, which finally fails several months later. And if you look at websites sell PC parts, many people complain of DOAs. Many, many DOAs are caused by ESD. Memory, CPUs, motherboards, HDDs, and other sensitive systems are often returned as DOA, driving up the cost of the PC enthusiast market and adding frustration. In research texts, they estimate the global electronic failures due to ESD to be 40-60% of the total failures over product life.

    So that little $5 ESD wrist strap is money well spent. Buy one and reduce your heartburn.

    Charles
  • 1 Hide
    Crashman , June 23, 2014 5:49 PM
    Quote:
    The other topic I wanted to comment on is ESD. I am an engineer and work with ESD issues everyday. It is a very real an poorly understood issue by many because of the often hidden or delayed failures that it causes. ESD many time causes walking wounded damage without an immediate failure, which finally fails several months later. And if you look at websites sell PC parts, many people complain of DOAs. Many, many DOAs are caused by ESD. Memory, CPUs, motherboards, HDDs, and other sensitive systems are often returned as DOA, driving up the cost of the PC enthusiast market and adding frustration. In research texts, they estimate the global electronic failures due to ESD to be 40-60% of the total failures over product life.

    So that little $5 ESD wrist strap is money well spent. Buy one and reduce your heartburn.

    Charles
    The vast majority of "DOA" returns are for undamaged products (simple things like having a standoff or cable in the wrong place that caused power fault/no boot/no damage are number 1, followed by fraudulent returns at Number 2). And the majority of damaged products have physical damage from the amateur technician cramming things together. I used to be in that business.

    The only problem with wrist straps is that most people don't want to be "tied" to anything. They're a great idea that's really rarely needed. Feel free to say otherwise if you live in the desert.

  • -1 Hide
    cutiemech , June 24, 2014 12:31 AM
    Skimmed through it but didn't saw anything about tools required for assembly like what screwdriver etc
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