How To Build A PC: From Component Selection To Installation

Step 5: Select Memory

There are a ton of options when it comes to system memory. From data rates to latencies to voltages, the number of combinations can become overwhelming. The easiest answer in the debate of what kit to buy sounds deceptively simple: just buy 1.5-volt DDR3-1600 (PC-12800) modules with CAS 9 timings. All Socket AM3+, FM2+, LGA 1150, and LGA 2011 processors are designed to support at least this memory speed. It's inexpensive as both 4 and 8 GB sticks, and it’s available in both dual- and quad-channel kits.

Yet there are noticeable performance benefits for similarly-priced DDR3-1866 (PC3-14900), particularly if you're using a CPU's on-die graphics engine for gaming. And this speed functions normally, even with processors that are not officially designated to use it (primarily older models or low-energy platforms). And the same easy benefits of DDR3-1866 are even available with most DDR3-2133 kits and modern performance-oriented processors.

The problem with recommending faster memory kits is that they often require at least some manual configuration. If you're not comfortable tooling around in your motherboard's firmware, they might actually drop you to lower performance levels.

You see, Intel’s XMP (eXtreme Memory Profiles) technology facilitates extended memory settings beyond the basic automatic-configuration technology called SPD. Though XMP originally allowed motherboards to set overclocked options like nonstandard voltages and data rates, most of today's XMP-capable modules operate at standard voltage levels and frequencies. Still, when you first boot up, they typically default to either DDR3-1333 or -1066. Going higher requires that you manually enable an XMP profile. Even some DDR3-1600 modules employ XMP (rather than SPD values) to achieve their rated performance levels, and this is particularly true of reduced-latency (CAS 7, CAS 8) modules.

Memory faster than DDR3-2133 is usually expensive and not really required. Our tests have shown that DDR3-2400 is barely beneficial, and only in situations where you're leaning on integrated graphics. We've even seen data rates above 2400 MT/s hurt performance as the motherboard attempts to increase stability.

In terms of memory quantity, Tom's Hardware recommends at least 4 GB for the cheapest Web surfing Windows-based systems. Gamers could probably get by with 4 GB, but we’re more comfortable with the 8 GB that has become the norm in high-performance machines. Few applications push memory needs past that point, though users of memory-intensive programs who also multi-task (such as Tom’s Hardware editors) can occasionally find an excuse to install even more. Users who need more than 8 GB usually know their needs in advance, based on experience with a previous machine.

Even those exceptional circumstances only push us to 12 GB, though 16 GB is easier to install in dual-channel mode (via two 8 GB modules). If you’re desperate for an excuse to add even more, installing RAM disk software (which uses some of your system memory as a virtual hard drive) could be your impetus.

Our memory reviews show a wide range of options, and buying name-brand modules with lifetime warranties from reputable venders is good insurance against unexplained system instability.

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32 comments
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  • AndrewJacksonZA
    "the power supply is actually one of the more important parts of a build"
    Thank you!!

    Or rather, let's do what the cool kids are doing and rather post a GIF:
    https://giphy.com/gifs/the-office-thank-you-michael-scott-1Z02vuppxP1Pa
  • Eggz
    Great piece for a lot of first-time builders. This should have a sticky somewhere on the site so it doesn't get buried :-)
  • jkhoward
    Quote:
    "the power supply is actually one of the more important parts of a build" Thank you!! Or rather, let's do what the cool kids are doing and rather post a GIF: https://giphy.com/gifs/the-office-thank-you-michael-scott-1Z02vuppxP1Pa


    Seriously, not enough people realize how import a good PSU is. I am working with someone is heavily overclocking an i7 and two 970 in SLI as well as 4 SSD and a few hard drives, a bunch of fans, with a 750W PSU.
  • jkhoward
    Also... I am digging the age of some of these images.
  • blackmagnum
    This article brings back embarrassing memories. https://giphy.com/gifs/the-office-thank-you-michael-scott-1Z02vuppxP1Pa
  • alidan
    Quote:
    Quote:
    "the power supply is actually one of the more important parts of a build" Thank you!! Or rather, let's do what the cool kids are doing and rather post a GIF: https://giphy.com/gifs/the-office-thank-you-michael-scott-1Z02vuppxP1Pa
    Seriously, not enough people realize how import a good PSU is. I am working with someone is heavily overclocking an i7 and two 970 in SLI as well as 4 SSD and a few hard drives, a bunch of fans, with a 750W PSU.


    unless i'm thinking wrong, isn't that within the power limits of a 750? im even assuming that each gpu is 300 watts and i know they shouldn't hit that even with the most aggressive of ocs

    granted there is a distinction between a good psu and a bad one, but im just assuming its a good one.
  • chimera201
    Motherboard slots haven't evolved much. Wished every slot was like a USB slot
  • turkey3_scratch
    612443 said:
    Seriously, not enough people realize how import a good PSU is. I am working with someone is heavily overclocking an i7 and two 970 in SLI as well as 4 SSD and a few hard drives, a bunch of fans, with a 750W PSU.


    Your point being... ?
  • renosablast
    Steps 1 and 3 should be combined, and step 2 comes after 1 and 3. You better worry about the CPU and motherboard combo compatibility before you worry about a graphics card.
  • renosablast
    Sorry, meant steps 2 and 4 before 3.
  • Dark Lord of Tech
    I love when you see a $1500.00 build with top quality components and then they have a $40.00 PSU listed with it.
  • Outlander_04
    IMO the very first component selection for a gaming build should always be the .... MONITOR.
    Decisions on where and how to spend the rest of the budget can only be made once you know the resolution , and whether its 60 Hz, 144 Hz or whatever else is available
  • MasterMace
    Gonna throw in my disagreement on the priority, mentioned nice and early in the article. The first thing you pick is never your case. There's 3 things you can decide to be your starting point when building a pc to make it a smooth ride; either, 1. Budget. 2. CPU 3. Graphics. By picking 1 of these 3 things as your starting point, you can have a very smooth build process. Does that mean you buy your case last? No, I've seen plenty of builds where the case arrives first as a way of storing the items, but when you want a solid build, your case is last priority, as it has no impact on your performance and restricts the size of your items.

    Even if you wanted to build an odd form factor, like an itx, you would still pick the cpu or the budget before the case.
  • Thank you for explaining ESD correctly. I have been annoyed with articles over exaggerating about ESD a lot. So just touching something metal can help? Well, next time I think I'll set a PC on my wooden desk instead of the carpet.
  • kunstderfugue
    Quote:
    I love when you see a $1500.00 build with top quality components and then they have a $40.00 PSU listed with it.


    The XFX TS Bronze 550 comes down to $43 ish from time to time and that's a mighty fine PSU to power a single graphics card build.
  • nitrium
    Quote:
    "the power supply is actually one of the more important parts of a build" Thank you!!

    While not unimportant, it gets far too much attention on the forum's here. PSU's are only relatively rarely the cause of issues, and I'll go out on a limb and say that virtually ANY modern 650W PSU (even ultra-cheap China garbage) will reliably power a single GPU and CPU, regardless of model or how much OCing you do to them.
  • Crashman
    269694 said:
    Quote:
    I am working with someone is heavily overclocking an i7 and two 970 in SLI as well as 4 SSD and a few hard drives, a bunch of fans, with a 750W PSU.
    unless i'm thinking wrong, isn't that within the power limits of a 750? im even assuming that each gpu is 300 watts and i know they shouldn't hit that even with the most aggressive of ocs granted there is a distinction between a good psu and a bad one, but im just assuming its a good one.
    You're exactly right. We've been using high-quality power supplies in most of our System Builder Marathon machines, and dual 970s was in one of the builds. The super-high recommendations you see from other sites are a response to most builders using mediocre-quality units.
  • Crashman
    416912 said:
    Gonna throw in my disagreement on the priority, mentioned nice and early in the article. The first thing you pick is never your case. There's 3 things you can decide to be your starting point when building a pc to make it a smooth ride; either, 1. Budget. 2. CPU 3. Graphics. By picking 1 of these 3 things as your starting point, you can have a very smooth build process. Does that mean you buy your case last? No, I've seen plenty of builds where the case arrives first as a way of storing the items, but when you want a solid build, your case is last priority, as it has no impact on your performance and restricts the size of your items. Even if you wanted to build an odd form factor, like an itx, you would still pick the cpu or the budget before the case.
    Exactly wrong. The first thing people do is say "I want a LAN box" or "I want a media player" or "I want a big gorgeous office PC". They're picking a case SIZE when they make those FIRST statements, so size comes first in the discussion.
  • beoza
    Quote:
    416912 said:
    Gonna throw in my disagreement on the priority, mentioned nice and early in the article. The first thing you pick is never your case. There's 3 things you can decide to be your starting point when building a pc to make it a smooth ride; either, 1. Budget. 2. CPU 3. Graphics. By picking 1 of these 3 things as your starting point, you can have a very smooth build process. Does that mean you buy your case last? No, I've seen plenty of builds where the case arrives first as a way of storing the items, but when you want a solid build, your case is last priority, as it has no impact on your performance and restricts the size of your items. Even if you wanted to build an odd form factor, like an itx, you would still pick the cpu or the budget before the case.
    Exactly wrong. The first thing people do is say "I want a LAN box" or "I want a media player" or "I want a big gorgeous office PC". They're picking a case SIZE when they make those FIRST statements, so size comes first in the discussion.


    I have to agree with you on this Crashman. Whenever I go to build a new system for friends or relatives I always ask what they're going for in terms of use. I like to go with the Form follows function principle which is that the shape of a building or object should be primarily based upon its intended function or purpose.
  • Libero
    Quote:
    Gonna throw in my disagreement on the priority, mentioned nice and early in the article. The first thing you pick is never your case. There's 3 things you can decide to be your starting point when building a pc to make it a smooth ride; either, 1. Budget. 2. CPU 3. Graphics. By picking 1 of these 3 things as your starting point, you can have a very smooth build process. Does that mean you buy your case last? No, I've seen plenty of builds where the case arrives first as a way of storing the items, but when you want a solid build, your case is last priority, as it has no impact on your performance and restricts the size of your items. Even if you wanted to build an odd form factor, like an itx, you would still pick the cpu or the budget before the case.

    Quote:
    Sorry, meant steps 2 and 4 before 3.

    It is same meaning as define a purpose and choose a case. When you buy a computer you must know what the purpose for first example for home/office, web browsing, gaming or multi-tasking. Budget also is depend to each person. So it is not CPU or GPU before case.
  • James Mason
    I wish the pictures of PSU weren't just all Corsairs. That leads people to believe that all Corsair PSUs are "good" PSUs, when we know a vast majority aren't, and the ones a new builder are most likely to be definitely aren't.
  • Crashman
    297651 said:
    I have to agree with you on this Crashman. Whenever I go to build a new system for friends or relatives I always ask what they're going for in terms of use. I like to go with the Form follows function principle which is that the shape of a building or object should be primarily based upon its intended function or purpose.

    It is same meaning as define a purpose and choose a case. When you buy a computer you must know what the purpose for first example for home/office, web browsing, gaming or multi-tasking. Budget also is depend to each person. So it is not CPU or GPU before case.
    Yeh, I should have just kept his last statement and deleted the rest before responding:
    416912 said:
    Even if you wanted to build an odd form factor, like an itx, you would still pick the cpu or the budget before the case.
    What he's saying is even if you choose a form factor first, you're still buying the other parts first. Which is a backwards way of saying that the order of the article, form factor first, makes sense...and he still wants to disagree...

    The problem is that one needs keep a general concept of the case in mind when picking the actual components. One can often pick the exact case to fit that concept at the end, but the "Define a purpose" leads immediately to form factor, and chopping the article off there only to come back to case selection doesn't really make sense.
  • Bjorn_2
    I miss one important piece of advice: do not install anyhting but your primary drive before installing Windows. I have recently gone through the nightmare of trying to aggregate Windows onto my primary drive when replacing my SSD for a bigger one. It seems that if you have multiple drives installed, windows will happily use all for various purposes. So feel free to install everything but please, before installing Windows, disconnect your secondary and other drives.