Designing the Perfect PC
Vito Cassisi
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Dec 2, 2008 3:06 PM
PC Design 01100101 with Vito Cassisi. And yes, that is binary for 101.
Building a new PC cannot be any easier. It’s a matter of slotting components into their respective sockets, and plugs into their female counterparts. But where most people fail is in the designing process, choosing the perfect parts for the ultimate price vs quality vs performance ratio. But this will no longer be an issue once you’ve learnt the way of the computer enthusiast; how we research, review and rate a product, and only allow the finer quality components grace our glorious desktops. It’s time to be enlightened into the world of PC design...
Deciding the computer’s main role
It’s human nature to seek the best components our budgets can satisfy, but often the appropriateness of these decisions is not a reflection of the desired end result. Hence we need to define what this ‘end result’ will be. There are four main categories:
Media Centre PC/HTPC
Home/Office/Multimedia
Gaming /Graphics Rendering (which incorporates enthusiasts and overclockers)
Server
Computers come in many form factors including the popular mini-ATX, ATX, and E-ATX. These define the physical size of the computer where mini-ATX is best suited to portable/HTPCs, ATX for standard office work or gaming, and E-ATX for high performance enthusiast systems and servers. Choosing the appropriate size depends on the main role of your PC. Size dictates the components that will fit, so it’s best not to choose the smaller form factor if you don’t need the smaller size. If you’re not sure about what size to choose, bigger is better. More room to work, upgrade, and hack. Oh yes, bring on the water cooling system.
Allocating the budget
The budget is the maximum you’re comfortable spending on the PC. Once you have calculated this, stick to it. If you’re wealthy and have quite a bit of money to burn, this doesn’t mean you should buy the best of everything. There’s often a large price gap between budget, performance, and extreme; however the difference in actual performance is rarely as straight forward. The gap between budget and performance components is often quite large compared to the gap between performance and extreme. Extreme components may only be, for example, 10 per cent more efficient than the performance parts, yet the price 50 per cent higher in cost. Try to find the best ‘bang for buck’ unless you genuinely require the extra performance.
The required parts
A computer system consists of the following components; use this as a checklist:
CPU
RAM
Motherboard
Graphics card
HDD or SSD
Power Supply
APU (usually integrated into the motherboard)
Optical Drive
Case
Basic external peripherals include:
Monitor
Keyboard
Mouse
Speakers
All these components (plus an operating system) make up a standard system. Be sure to consider all these parts in your design.
Recycle and save
No, this is not about scavenging aluminium cans for the 5c rebate, but rather parts from your older machine. Peripherals such as the monitor, keyboard, and mouse can be reused if they still suit your current needs and desires. Generally, processing parts such as the graphics card (or GPU), CPU and RAM will be outdated, and should only be used if suitable. A previously used OS can also be installed provided they aren’t OEM or insufficient for modern use i.e. Windows ME (read: Burn it. Now). Vista 64-bit is recommended for new systems due to its modern CPU scheduler, enhanced security and ability to address stupid amounts of RAM.
Selecting components
This is often the toughest step for system builders. Choosing suitable components requires a fair bit of researching including reading reviews, benchmarks, and forum threads. Never buy parts because they ‘sound cool’, have an appealing advertisement, or because your friend has one. Chances are that the product is not the best value in respect to your individual situation. The following sections will describe methods of choosing each system component.
The Motherboard
A motherboard is a series of busses and chipsets that control the communication of each connected system component. Typically it is the last part to be chosen as it needs to be compatible with all other selected components. That being said, it should be considered throughout the course of the build.
There’s no hard and fast rule when selecting a motherboard, but a general process should be followed to maximise the success of the build:
Selecting the desired chipset: The chipset defines the choice of CPU(s), the GPU bandwidth and scalability, amount and type of RAM, and the overclockability of the system. Generally an NVIDIA chipset allows SLI (Scalable Link Interface), the linking of two or more identical NVIDIA GPUs for combined graphics processing. On the other hand, the Intel chipsets allow Crossfire, which enables two or more ATI GPUs to run in unison. Select the chipset which sports the features you desire (this will require some research), and look out for any new chipset releases. The latest 4-series GPUs from ATI work best in Crossfire when used with an X48 chipset. Although Crossfire is compatible on all current Intel chipsets, the performance takes a hit without the added bandwidth that the X38/X48 chipsets offer. Current NVIDIA cards aren’t as fussy in terms of SLI bandwidth, likely due to their use of lower bandwidth GDDR3 memory, and therefore work well in a range of NVIDIA chipsets. The current NVIDIA picks include the EVGA 750i and 780i FTW boards, which support 2-way and 3-way SLI respectively, while allowing impressive overclocking on the FSB.
Select the form factor: Depending on the purpose of your system, you may need to get a particular sized motherboard. Most enthusiasts will be looking at the ATX and EATX form factors for their range of features and compatibility with high-end gear.
Select the socket type: Unlike in the past, AMD and Intel CPUs use different sockets. Once you’ve decided on the CPU, the choice between AMD’s AM2+ and Intel’s LGA775 sockets becomes clear.
Select expansion slots and ports: The number of expansion slots defines the amount of cards that can be fitted at once. If you intend to install multiple GPUs, then full size PCI-e 16x slots are required. There are also PCI-e 1x slots which can be used for TV tuners and other less demanding components. Other important ports/sockets to consider include SATA, IDE, USB, ethernet and audio.
Select integrated components: Do you require inbuilt audio or graphics capabilities? If this is the case you will need to select a motherboard with the appropriate integrated chipsets. Most motherboards include inbuilt audio (usually of Realtek branding) however integrated graphics chipsets are commonly found in lower-end mini-ATX solutions or specialised full ATX solutions. Being enthusiasts, any inbuilt graphics chipsets will be overshadowed by monolithic floating-point marvels of the dedicated GPU variety. ‘sif integrated.
Enthusiast specialities: Design advantages such as solid state capacitors and high FSB capability help when overclocking a system. The best way to determine motherboard performance is to seek benchmarks and user-submitted overclock results.
Once you find a few products which match your criteria, seek out comparisons, reviews, and benchmarks for each. This will eventually provide you with a clear winner, and if not, go for the cheaper option with the best warranty. Unless, of course, you have money to burn (in that case, send some our way).
Central Processing Unit (CPU)
The CPU is often considered the most important component within a PC. Whether this is true or not is up for debate, but rest assured, the PC will not function without one. Technologies such as NVIDIA’s CUDA platform may one day make CPUs less important due to the inherent architectural advantages of modern GPUs, but that day is while off just yet. A growing area of interest resides with GPGPUs, General-Purpose Graphics Processing Units, however. These allow otherwise dedicated GPUs to be used for general purpose tasks which the CPU is normally assigned to; in doing so the parallel processing nature of GPUs struts its architectural speed advantage.
Despite this technological advantage, GPGPUs are still a distant future in terms of practicality mainly because of the lack of data prediction and the specialised instruction sets they require; therefore a CPU is still well and truly important. Choosing a CPU isn’t particularly complicated if you follow a few simple guidelines. Firstly the main components of the Central Processing Unit must be established.
Cache: Cache is high-speed memory in which the CPU stores data to be processed. The larger the capacity of any given level of cache, the greater the performance. Data which does not fit within the integrated CPU cache is sent off-die to be stored in RAM. On die cache is split into layers, often two or three, each decreasing in speed and increasing in capacity respectively. Therefore, L1 cache is the fastest yet smallest capacity, L2 is larger and slower, and L3 (if the CPU contains such a level) is slower still with the largest capacity.
Cores: The amount of cores defines how many threads that can be efficiently processed at one time. This improves performance, although many applications are still limited to utilising one or two cores at a time. The operating system used also influences the performance of multiple core systems; Vista is better than XP in this regard.
Clock speed: Clock speed is often misused when comparing CPUs. The clock speed is the amount of clock cycles per second measured in Hz (or GHz). Clock speed is not an appropriate method of judging processing performance because it doesn’t define the amount of data being processed within each clock cycle.
Multiplier: The multiplier is a numerical value which defines the clock speed of the CPU. Higher multipliers are sought after by overclockers, but are usually accompanied by a hefty price tag. Finding the right balance between price and multiplier is a major factor when choosing budget overclocking gear.
Choosing a CPU
CPU selection encompasses the following performance groups:
Performance/Enthusiast/Overclocker: This clique strives to find the highest multiplier they can within their budget. This is also dependant on other key features such as cache and cores, although higher values may decrease overclocking potential. Also, smaller manufacturing processes are desired due to the reduced heat and reduced power consumption.
A great example of budget CPU overclocking performance includes the E8500/E8600 and Q6600/Q6700 Intel CPUs. With 9.5x/10x and 9x/10x multipliers respectively, their overclocking potential is nothing short of mind blowing.
Server: Servers often use specific CPUs designed for accurate computation and high stability, such as Intel’s Xeon and AMD’s Opteron range. These CPUs typically contain larger cache capacity and are of a higher grade binning.
Binning is the process of sorting components into performance ‘bins’. CPUs are tested until they are no longer stable, and when this limit is reached, they are placed into a particular ‘bin’ depending on the performance demonstrated. It’s not uncommon for server CPUs to use different sockets than desktop CPUs, so keep this in mind when choosing a motherboard/CPU combo.
What to research
Using a search engine such as Google is helpful when locating information in relation to the details above. Find model names of CPUs within your price range, and compare benchmarks on tech sites. The best way to find suitable parts is to browse reputable computer forums (such as Atomic) for advice.
Never select a CPU (or any component for that matter) based solely on brand name; always seek benchmarks which show how particular models perform from each brand.
The GPU (Graphics Processing Unit, or graphics card)
GPUs are the driving force for graphically intense applications such as games, 3D modelling/CGI and video editing. Recently they have been increasingly popular for calculating large amounts of data in place of existing CPU-based processing clusters, mainly due to their superior parallel processing nature.
The main components of a GPU include:
VRAM: VRAM is onboard memory used to store textures and data waiting to be processed by the GPU core, similar to how the CPU accesses RAM on the motherboard. VRAM is based on the GDDR architecture. Later architectures have larger bandwidth allowing higher transfer rates between the core and memory.
Core: The GPU core is the main onboard processing unit. Similar to that of a CPU, but primarily used to calculate floating-point calculations for graphics tasks.
Pixel Shaders: Pixel shaders convert 3D co-ordinates and instructions into 2D data, or ‘pixels’, for display on the monitor. The more shaders the better as they act as parallel processors. As with most components, in most cases the performance gain is dependent on the unit as a whole, such as overall architecture, rather than specific elements such as this.
Clock Speeds: The VRAM, core, and shaders each have separate clock speeds. Older GPUs often link the shader and core clocks so that they are in the same ratio; increasing the core will increase the shader. The higher the clock speed the better when comparing the same model amongst different brands. Comparing different models by clock speed is not a true indication of performance; do not do this.
Scalability: Modern GPUs allow two or more cards to be linked to work as one. Some models may have enough connectors to support three or four cards at once instead of the typical two card collaboration. SLI and Crossfire are the main technologies for NVIDIA and ATI cards respectively; most motherboards only support one or the other. Some high end GPUs come in dual core and dual PCB (Printed Circuit Board) models, which incorporate inbuilt scalability between two onboard GPUs.
Choosing a GPU
As with most components, the choice of GPU depends on the budget and intended usage. It’s wise to look out for the following factors in each computer category:
Performance/Enthusiast/Overclocker: High performance GPUs generally have high clock speeds, large memory capacity, and often incorporate dual core/PCB solutions. These cards are best for high end systems which need the extra power. In particular, overclockers prefer smaller manufacturing processes when choosing a GPU to allow higher overclocks with minimal heat.
Server: Generally servers are CPU intensive and don’t require much GPU power. Integrated solutions are fine for file, print, and web servers.
The models to look out for include ATI’s 4870 and 4870X2, and NVIDIA’s GTX280 for high performance systems.
What to research
There are three main GPU manufacturers; NVIDIA, ATI and Intel. NVIDIA and ATI make expansion cards while Intel focuses mainly on integrated solutions. The manufacturer websites provide a list of models they offer, so it’s just a matter of searching online for comparisons of models in your price range. Larger monitor resolutions require more VRAM, so be sure to compare benchmarks using the same resolution as your monitor.
The RAM (Random Access Memory)
RAM is used as the largest cache of the CPU due to its high capacity and low manufacturing cost. A large amount of RAM is essential for new PCs, which are heavily driven by multitasking and an array of services. A common guideline is to buy as much RAM as the budget (and your OS) allows. RAM is made up of the following generalised components:
Capacity: The capacity of RAM is measured in GB (or Gigabytes) on modern sticks. The more the better, but anything over 3GB requires a 64-bit OS and CPU to be accessed. All modern CPUs are 64-bit, so this shouldn’t be an issue.
Clock speed: The clock speed defines the speed at which the data can be transferred to and from the RAM. Higher clock speeds are preferred when comparing RAM modules.
Architecture: RAM architecture includes DDR1, DDR2 and DDR3. Each generation of RAM strives to improve bandwidth and overall throughput of data transfer. A side effect of this advancement is higher latencies; however modern systems benefit more so from higher clock speeds rather than lower latencies.
Latency: Latency is the gap between a request for data by the CPU, and the transmission of said data. Although lower latency is preferred, it isn’t important compared to larger clock speeds.
Choosing RAM
DDR2 is the cheapest solution at this point in time, while DDR3 has theoretically higher performance. If going with DDR3, look at modules which are over 1066MHz, otherwise you’re better off with the cheaper and lower latency DDR2 modules. If the price is too high, get some generic (yes, generic are fine) DDR2 1066MHz sticks. They are great value for money.
Researching RAM
With RAM it’s a matter of selecting the cheapest sticks with the highest clock speeds. Latency isn’t much of a performance factor on modern platforms, so don’t choose lower latency models if the cost is significantly greater. If overclocking, research benchmarks and user results.
[subhead] The HDD/SSD (Hark Disk Drive/Solid State Drive)
The humble primary storage device comes in two consumer flavours, the HDD and SSD. Look out for the following when choosing a storage device:
Platter Density: Regarding HDDs, platter density refers to the capacity each platter holds. The greater the density, the faster the transfer speeds will be due to the minimal movement required by the read head.
Platter Speed: The speed at which the platter rotates is measured in RPM (Rotations Per Minute). The faster this rotation, the smaller the seek time is in HDDs. Regular drives are 7200RPM, high-end drives are 10000RPM upwards.
Sustained Write/Read: The speed at which the drives can transfer data to and from the HDD or SSD. The write speed is commonly a measurement of the speed of cached data being written to the main storage platters (or flash in the case of SSDs). Faster is better, speed is typically measured in MB/s .
Capacity: Capacity is fairly obvious – the more capacity there is the more room for data such as software and documents.
Cache: The cache stores data ready to be written to the HDD. Greater capacity generally improves write speeds.
Choosing a HDD/SSD
There are many factors which determine the appropriateness of a HDD or SSD for your intended setup.
Performance/Enthusiast/Overclocker: The main focus for performance systems are high density platter 7200RPM HDDs, Velociraptor high speed drives, and high end SSDs. The first option is cheapest and often the appropriate choice.
Server: High-end servers use SCSI drives which are faster variants similar to that of Western Digital’s Velociraptor range. These drives are expensive and require a SCSI capable system.
What to Research?
When looking at storage devices, its best to look for high density platters with large capacities. SSDs should only be factored in if your budget can cater for the exorbitant costs. High transfer speeds can be determined via benchmark comparisons between models.
The PSU (Power Supply Unit)
The PSU is often the most exaggerated component within a PC. It’s either chosen with too-limited power (unintentionally, of course), or an excessive amount. The main misconception is the wattage rating. PSUs should not be compared with this alone because of two other underlying factors: the +12v rails and the overall efficiency. More information on these elements can be found in issue 89 of Atomic or here on this site.
Choosing a PSU
There are a few steps to follow when choosing a PSU.
What is the power draw from your system? Find out the power draw of each component at maximum load, then find a total. Seek more than this amount; an extra 50 per cent wouldn’t go astray. This ensures that future upgrades can be fitted, and that the efficiency doesn’t suffer. Factor in the efficiency of the PSU, an 80 per cent efficient 500W PSU is really only useful at 400W and under. Too much load on the PSU can cause failure.
Find a PSU with the correct wattage and 80-plus certification. This means the PSU is at least 80 per cent efficient.
Narrow down the search to high amperage (A) +12v rails.
What to research?
Research the amount of rails, efficiency, amperage, and wattage of PSUs in your price range. Online reviews and computer forums are informative sources to guide you.
The Optical Drive
Optical drives are simple to choose, there’s usually only one decent one at any particular time. For the last few years this has been the Pioneer range. This may change; the only way to select the best is to look at reviews and forum opinions. Apart from this, the write speed, firmware, and build quality are the main factors of performance, accuracy, and durability.
The Case
The case defines which components will fit (i.e. form factor), how many components will fit, and the quality of cooling if using air alone.
Cable management features: Some cases allow cabling to run under the motherboard, or they supply channels for cables to run through. Neater cables help improve airflow.
Number of 5.25in bays: These can be converted to 3.5in bays for extra HDDs if need be.
Cooling/Airflow: Computer components need constantly circulating air to keep from overheating. Fan placement is important, as well as the number and wind pushing power (cfm) of the fans used.
Form factor: As stated above, the form factor defines the size of the components that will fit. e.g. ATX is smaller than E-ATX.
In the end, case choice comes down to personal preference. Match the size of the components with the case. If the case is too small, then choose a larger one, otherwise look into smaller components.
Overall Component Selection
There are many peripherals to cover, so the following will explain a general method of component selection.
Take note of the specifications and outcomes you desire. With this information you can easily sort through the several products on offer. Research and sort through reviews, benchmarks and forum opinions. An example for a GTX280 GPU would be to search “GTX280 review” or “GTX280 benchmark” in a search engine.
Ensure that the products are compatible with existing components. This includes drivers for the OS or physical connections such as ports and expansion slots.
Searching for components is often complex because of the array of pricing across several stores. A solution to this is using a retail search engine such as StaticICE.
If you’re still stuck between a few products, search for comparisons. An example is “GTX280 vs 4870”, which in this case is comparing the GTX280 with the 4870 GPU. Often forum threads will show up in the results – use this to compare user opinions.
Select, of what’s left, the cheapest component with suitable warranty/support.
Putting it Together
Before purchasing your shiny new components it’s important to consider their compatibility in terms of size, specifications, and power requirements – as outlined above. If in doubt, ask. The members of the Atomic forums are willing to help, just be polite and informative regarding your question.
When you’ve chosen all the parts, bought them, and examined their pretty boxes – it’s time to build it! There are many guides on the internet to, well, guide you, or you can ask the kind gentlegeek at Atomic for some assistance. Just remember to have fun while constructing your awe-inspiring rig!
And as always you can find fantastic advice on the latest gear in our forums, so head over, sign up and start asking the locals!