Anyone active on Super User has encountered the infamous shopping requests before, and you can’t really blame them for trying: They don’t know what they need, and here’s a website about computers where people understand all the latest gadgetry, standards, and most importantly, the endless acronyms.
But we’re missing the most crucial part: We don’t understand their needs.
After spending an hour or two working with several others in the Super User chatroom to help a user make heads or tails of how to translate his needs into hardware, it became clear that for all the questions about how to understand and judge performance vs. needs for individual components of a computer, they were extremely spread out over the site, which made them as a whole hard to find, especially if you didn’t know what you were looking for.
Super User needed a new community wiki. This week, the community is collectively wondering and defining How do I know what hardware to buy to meet my needs?:
- How do I find out if a given CPU will be enough for a certain game or application that I want to run?
- How do I find out if a given graphics card is powerful enough for a certain game or application?
- What is important when looking at motherboards?
- How much memory do I need?
- How do I know how much wattage I need for a power supply?
- What size case do I need?
- What relevant standards do I need to read up on and be aware of?
- What “gotchas” do I need to be on the lookout for?
All of this information should still apply regardless of whether you are buying a pre-configured system or building your own from scratch. Configuring a system online at a retailer such as Dell, Apple, or HP still has a pretty wide range of systems and configurations, so making heads or tails of the options provided there is still necessary – you’re trading wide selection for the comfort of knowing that all the parts should work well together and letting someone else assemble and configure it.
So… just how do you answer all that? The community had the following information to offer:
First, understand your needs
It’s impossible to answer “Is this enough?” until you know what ‘enough’ is. This is often determined by the applications and technologies that you plan to use some of which are easy to define (“I need Firewire for my camera”) to very general and open ended (“I want to play games!”). The key to this is understanding what kind of applications you plan to use. Applications generally fall into several categories (which are not mutually exclusive):
- CPU-bound, or programs that are limited by the capabilities of the processor
- GPU-bound, or programs that are limited by the capabilities of the graphics card
- Memory-bound, or programs that are limited by the amount of RAM available to them (This will double up as IO-bound, since most operating systems use the harddrive as memory once they run out of the real stuff)
- IO-bound, or programs that are limited by the capabilities of the hard drive
The best way to find out this kind of information about specific applications is by looking at reviews. You can search the web for “<application name> performance” to find guides on how to improve performance for those applications. The parts they recommend improving are what you should look into investing a bit more in when selecting yours.
This is also when you want to make note of important technologies that you want to have available to you. Often you can supplement a system through add-in cards later, but planning ahead can simplify things in the long run when onboard (included on the motherboard) will suffice.
Now that you know what limits the applications you plan on using, you need to find out what hardware will actually provide you the performance that you want. The easiest way to do this is to look at benchmarks and reviews to see how applications really perform in given hardware configurations. Tom Wijsman recommends this information:
Tom’s Hardware has an extensive library of performance benchmarks and reviews for all kinds of Graphics Cards, Hard Drives, Processors, Power Supplies, Memory Cards, Servers and Monitors. Alongside performance you will also be able to find charts for noise, temperature and a set of other characteristics. In the Benchmarks section of PassMark Software you will find comparison lists for Processors, Video Cards, Hard Drives and even full systems. They aren’t extensive in the mather of detail, but a ton of hardware benchmarks are incorporated in the system on a daily basis which makes it very accurate. When buying a laptop, make sure you don’t forget to check Notebook Check. They benchmark and review laptops inside out, they even do Display Brightness Distribution, Noise Levels and Body Temperature Spread so I doubt if you will find websites that go more into detail on a broad sets of laptops than this website does. Other than those, you can query
[hardware model name] benchmarks…
And i_grok offers:
As previously stated here, the benchmark sites are too numerous to count. I’d like to call out one that I’ve used successfully for many years: http://www.gpureview.com/
Second, understand your budget
Everyone would build the best computer they could if price was no matter; sadly, it is. With limited resources, how do you know how much to allocate to which component? If you only have a little room left in your budget, spend it on the following components as necessary:
- Memory Size: Memory is cheap these days, and programs are growing larger and larger. For any computer that is running low on memory, adding more will make the entire system feel orders of magnitude faster. (How do you know if you have enough already? Try this: When using the computer, try to alt-tab between open applications. If the system hesitates or is slow in pulling up the application or letting you use it, then you’re out of memory and could see benefit from a bit more)
- Hard drive Speed: SSDs are a world of difference compared to their platter cousins. If you can upgrade to an SSD, do so. Upgrading to a 7200RPM drive from a 5400RPM drive is also a good speed increase if you’re stuck with a conventional hard drive.
- CPU Speed or GPU Speed, depending on usage: GPU for GPU-bound games, CPU for multitasking and CPU-bound applications and games.
- Memory Speed: For those that want to get every bit of performance out of memory-intensive applications. This usually isn’t too noticeable unless it’s a big upgrade and it was all that was limiting you before.
Third, understand your hardware
The processor is what runs all the software on the system, and is basically the general manager that tells everything else what to do. As a general rule of thumb, you can’t compare processor speeds between manufacturers, and even within a manufacturer different architectures can have wildly difference performance per gigahertz. The best way to compare processors is through benchmarks. Multiple cores only adds to this mess, because how much benefit a given program will see on a multi-core processor varies wildly.
In theory, a quad-core, 3GHz processor could do as much work as a 12GHz processor, but in real life you’ll almost never see that kind of performance in a single application. Look for benchmarks involving the processor you’re looking at and the applications or games you’re planning on using with the system. If all else fails, ask on SuperUser how well a program utilizes multi-core setups.
You want to make sure that
- The socket on your motherboard matches the socket used on the CPU
- The motherboard supports the CPU out of the box, or with a BIOS update (if you have a spare CPU that works for you to update the BIOS)
The memory is where running programs store their data. The speed rating on your memory doesn’t matter too much unless you’re really trying to squeeze every last bit of performance out of your system; Total amount will play a much bigger role in performance for most people. When the system starts to run out of memory, it begins to use the hard drive as memory (via “swapping” or “paging”); this causes the system to slow down significantly, since the harddrive is several orders of magnitude slower than main memory. With memory as cheap as it is, be generous and buy plenty.
Make sure to use a 64-bit OS that can access all of the memory, too! You can check the architecture of your OS by running “
uname -i” on *nix machines, or by looking at the system properties in Windows (Right click on My Computer -> properties). If you already have a 32-bit version of Windows Vista or Windows 7, you can use that same key to reinstall with the 64-bit version. All you need to do is get a copy of the proper installation media by borrowing from a friend and using your own license key.
Another easy way to tell that you’re out of memory if you have Windows Vista or Windows 7 is to open the run dialog (Win+R) and type “
perfmon /res“. Select the memory tab and watch the graph for “Hard Faults/sec”. If this goes above 0 for more than a second when switching between or using applications, or if there is very little memory marked as Standby or Free, then you’re out of memory and could see benefit from more.
You’ll often see “Double-channel” or “Triple-channel” being talked about when memory is advertised. Normally on a system, the processor can only access one memory chip at a time, even if you have multiple memory chips. Multi-channel systems divide the memory slots into banks, which the CPU can access concurrently. Read through your motherboard’s documentation to see how you need to arrange memory in the slots to enable double or triple-channel benefits.
For example, a motherboard might have 4 slots, alternating blue-black-blue-black. The manual should tell you that the first two are on a separate channel than the second two, and if you only have two memory chips (you don’t have to fill every slot on the motherboard) then you’ll want to place them in both blue slots, or both black slots (but never one in blue and one in black; it’ll work, but it will be sub-par).
When buying memory, ensure that
- The generation of memory matches what the motherboard supports. Laptop memory is different from Desktop memory.
- You have a 64-bit OS, or you will be limited to less than 4GB of memory regardless of how much you have physically installed in the machine.
- When buying for a multi-channel system, you want to buy matched pairs, or a package that contains one or more memory modules for each channel in your system.
Graphics Card (GPU)
The graphics card is responsible for rendering all the graphics and driving them out to your monitor. Like the CPU, there are numerous options and the best way to compare them is through reviews and benchmarks from websites online. Like multiple cores on a processor, a computer can have multiple graphics cards installed that work together. For nVidia cards, this technology is called SLI; for ATI/AMD cards, it’s called CrossFire. Both require motherboard support to function, and only work with certain GPU combinations. Also like multi-cored CPUs, some applications are able to take advantage of this, while others do not see significant improvements from multiple GPUs. Benchmarks, benchmarks, benchmarks!
You need to make sure that
- Your motherboard has a slot that matches the graphics card
- Your power supply has PCIe power connectors for the graphics card if the card needs them (And if the card has connectors, then it needs them).
- The display outputs are compatible with your monitor cables. Usually this can be fixed by an adapter.
- Your case has enough room. Some graphics cards are quite large!
- Your power supply can support the card under full load.
- Your case has adequate cooling for the card.
- If you plan to use SLI or CrossFire, make sure the motherboard supports it.
The hard drive is where all the data is stored on your system, and comes in two forms: Disk, or platter drives, and SSDs, or solid state / flash drives. Most use a SATA connector to interface with the motherboard or an add-in card (Some still use PATA or IDE, but that standard is being phased out, so do not buy into it)
This is your conventional hard disk that’s been around since the dark ages. It’s slow, but it makes up for it with capacity. If buying multiple platter drives for RAID use, buy each one from a different manufacturer, unless you can guarantee they come from different batches. This is because hard drives from the same batch tend to fail together, and a RAID1 is useless if the second drive fails before you can replace the first failed drive! As a rule of thumb, platter disks are cheap, and data always fills the amount of space allotted to it, so don’t worry about getting too much.
These are your little USB thumbdrive’s big brother. Big, bad, and faster than the speed of light. The problem is warp technology isn’t cheap – you’ll probably want a large platter drive to keep your data on, and a much smaller SSD to install your OS and programs onto. Because of how expensive these drives are, there are also hybrid drives that are being produced, which combine an SSD with a regular harddrive, using the SSD to cache the most often used files. This can provide speed benefits close to what a SSD does, but doesn’t have such tight restrictions on space.
When buying a harddrive, keep the following things in mind:
- You need to have a SATA port on the motherboard for each drive you wish to use. There are add-in cards, called “hard drive controllers” which can provide additional SATA ports if you need more.
- Platter drives don’t really utilize more bandwidth than a SATA generation 2 (“SATAII” or “SATA 3Gpbs”) port provides, but newer SSDs can surpass that. If your drive uses a later generation of SATA (such as the SATA generation 3, or “SATAIII” or “SATA 6Gbps”), make sure you have that type of port to support full speeds. SATA is backwards-compatible as far as the generations go, but you will be limited to the speed of whatever port you plug it into.
- Don’t rely on SSDs for storing critical information. Jeff Atwood has a post regarding longevity of the drives: Worth every penny, but they still fail. Keep them backed up to a platter drive until lifespan improves!
This is the overlord that ties your whole system together and keeps everything running smoothly. Other than matching up the current socket with your CPU, the biggest question about selecting a motherboard is making sure it has all the technologies that you want to have in your next computer. While most can be added later through add-in cards, it’s often cheaper to get them built into the motherboard when you buy it.
Expansion slots are how you add additional functionality to a motherboard, such as additional USB or SATA ports, or high-end graphics processors. Most consumer motherboards have either PCI or PCIe slots, anywhere from 1 to 7 depending on the form factor of the motherboard. PCI and PCIe slots are not compatible, so ensure that any add-in cards you’re planning on buying match up with an available slot in your system. Don’t be afraid to get a motherboard that has no PCI slots; PCI is being phased out at the time of writing, as PCIe is a much more versatile standard that supports faster speeds. Generally speaking, different PCIe generations are backwards compatible, with parts operating at the lowest common denominator with regards to speed. Be careful not to confuse the generation with the number of lanes!
PCIe 2.0 is mainstream, with PCIe 3.0 just around the corner at time of writing. This is completely different from the 1X, 4X, 8X, or 16X you might see next to it, though. The multiplier is the number of lanes that a card requires to fit in a slot on the motherboard; smaller cards can fit into larger slots, such that a PCIe 1X card can fit into a 4X or a 16X slot, but the reverse is not true. The first 16X slot is usually the primary slot, and that is where most motherboard manufacturers expect the graphics card to go. If you plan to have multiple graphics cards, read the manual for your motherboard to see how the lanes are arranged to achieve best performance (often times a lane is split up between multiple slots so placing graphics cards in the right slots can reduce the contention for these lanes).
The essential notes about selecting a motherboard are:
- The socket on the motherboard needs to match the socket of the CPU
- The motherboard form factor needs to fit inside the case
- The motherboard should have enough expansion slots for all the add-in cards that you want to use
- The motherboard should have enough SATA ports for all of the hard disk and optical drives you plan to use
- The motherboard should support the generation of memory that you are using
The optical drive is what reads and writes DVDs, CDs, and Blu-ray disks. You will probably use this to install the operating system (if you’re building your computer yourself), and you need to check that the connector matches what your motherboard supports; An optical drive will use either SATA or PATA connections (like a harddrive), though PATA is being phased out and you should shoot for a SATA drive. Mehrdad also offers this note of warning:
Have a DVD burner! Don’t give it up simply because you think you won’t need it, because it will make your life easier.
There’s not a lot of variation between drives – just pick one that reads the formats that you want it to read, and writes the formats you want it to write.
The power supply is the unsung hero of the computer. Nobody really mentions it, when every component in the computer depends upon it for a clean, stable electrical feed. You don’t have to get the most expensive power supply, but you want to get a quality power supply that is enough to support your needs. Tom Wijsman offers:
The PSU converts 220 [or 110] volt AC to the 12, 5 and 3.3 volt DC that your computer’s hardware needs. These voltages are distributed through connectors, also called rails, to individual hardware components inside your computer. The 12 volt rails run the fans, hard drives and optical drives, while the 5 and 3.3 volt rails power the CPU and other electronics.
In the first place, it’s important that the power supply can support your computer hardware in terms of wattage. Go through a power supply calculator or sum up all those wattage’s listed in the technical specifications, then look for a PSU that supports this amount of wattage. Better higher instead of lower than the wattage.
Next, check if there are enough power supply connectors and if they are compatible with the motherboard. Other things to look at are the ratings, quality and safety considerations; but in overall you should be fine if you watch out for that you don’t go for a bad quality one.
You do want to make sure that your powersupply
- Provides enough power for all components under max load, or the computer could become unstable and randomly reboot. (Use the calculator link in Tom’s quote above).
- Has enough PCIe connectors for all graphics cards or other add-in cards that need them.
- Has enough 4-pin molex connectors or SATA power connectors for the harddrives and optical drive. (You can get a molex-to-SATA-power adapter if you need)
The case of the computer doesn’t deal much with performance, and generally is much more dependent on personal style and preferences. The key things to match up are:
- It should support your motherboard’s form factor
- It should have enough 3.5″ drive bays to hold all the hard drives you plan to use
- It should have enough 5.25″ drive bays to hold all the optical drives you plan to use
- It should be big enough that it can hold any add-in cards you selected, including the graphics card. Some of the high-end cards are over 10″ in length, so make sure that this leaves enough room if the hard drives are placed between the cards and the front of the case.
Shinrai provides us with the following snippet on cooling:
One thing to consider, if you’re going for a relatively high-powered machine (high end graphics cards for gaming or CAD, a multi-core processor that you intend to overclock) is chassis cooling. Reviews are usually pretty good about pointing this out, but you want something with good airflow and plenty of places to put the fans. Consider upgrading the fans if it’s a heavy use machine like this – they’ll be quieter and last longer.
Putting it all together
Getting hands-on experience with the hardware yourself is a great way to see how it is all connected together, and greatly helps to break down the idea that the computer is a big black box inside of which magic happens. Assembling your computer yourself usually takes an hour or two depending on how much you’re trying to fit into the case, though for a first build, it might be good to just set aside the whole afternoon. Tom‘s question, How do we assemble a computer properly?, aims to cover the basics of putting the parts together, but two key points to remember when working with computer parts are as follows:
Don’t force anything
Many computer parts are delicate and have pins that are easy to bend. It’s not much fun killing a $400 processor because you broke a pin on the bottom. Most computer parts are designed to have connections that require firm, but not forceful pushes to properly seat them. If it requires a significant amount of force, then there’s a good chance the component isn’t in the socket correctly, or doesn’t fit at all (which would mean that it’s not compatible, and you didn’t do your homework in understanding your hardware). Everything is notched or asymmetrically designed such that it only fits one way into the designated socket. Make sure all the notches are lined up before applying any pressure!
Keep yourself grounded
Processors and other ICs are extremely sensitive to static electricity, which can damage and destroy a chip’s ability to function. Antistatic Wrist Straps are sold that will ground you to the case while you are working, which will neutralize electrical potentials. You can do this manually by making sure you keep some part of your skin in contact with metal on the case at all times and not wearing shoes or socks while building; just be careful not to forget!
But there’s so many options!
Yes, yes there are. Most of the time it doesn’t matter, though you can see when it does by reading the reviews on websites like NewEgg.com. Good hardware is popular, and popular hardware gets lots of reviews. But don’t just look at the numbers, actually go through and read the reviews. You’re about to spend several hundred dollars, make sure you do your research beforehand to save yourself costly headaches down the road.
For those of you that want a jumping off point to get a particular build started, There’s a wonderful guide here that lists the latest hardware (or should, if it’s kept up to date. Always check the date at the bottom!) and has incremental builds. A good way to use this guide is to start with a build that’s about 80% of your total budget, and then upgrade the individual components that are crucial for your needs.