## hpr1258 :: How to Build a Desktop Computer

 Show Notes for How to Build a Desktop



Build vs Buy
Do you have the interest and time to
research and build a desktop computer?
You probably won't save a lot of money,
but with all the research you may get better quality parts.
You will know exactly what's in your
system should issues or questions ever arise.


Gather requirements
Define the purpose of the system 

Use:  gaming,
video/photo processing, web browsing/documents
Applications
should drive most of your hardware decisions.
Data protection: 
how much data, how resilient (on-site mirroring, RAID vs. off-site)
Power protection: 
surge suppression, UPS
Physical
protection:  keyed case lock (disassembly prevention), cable anchor


Define a budget 

Decide what are
you willing to spend (max, target, min)
  Check
off-the-shelf models to get the going price points
Understand there
are trade-offs and if everything is needed at once
Adding
capabilities later can help with sticker shock
If you have time,
buy components when prices dip
Be careful about
return policies...some 30 or 90 days


Learn about current technology &
prices
Core:  CPU,
memory, motherboard, graphics controller, power supply
Storage:  solid
state drives, rotating hard drives, removable media (DVD, USB)
Auxiliary:  audio,
monitor, power protection, web cam, printer/scanner, backup drive
Interfaces:  SATA,
IDE, DDR2, DDR3, PCI, PCI-e, USB, eSATA
Determine
approximate price range
Where to research
this stuff:  Wikipedia, Tom's Hardware, Anandtech, Specs on vendor web sites
Where to shop:  NewEgg.com,
Amazon.com, Dell.com


Understand compatibility
Hardware-Hardware
compatibility
	Check qualified
hardware list (QHL) on CPU/memory/motherboard
	Also known as CPU
support list, memory support list, qualified vendor list, etc.
	If you can stick
to the QHL parts, h/w compatibility is more assured
Hardware-Operating
System compatibility 

Drivers, either
built into the OS or from vendor web site
Pay attention to
32-bit vs. 64-bit in both operating systems and drivers
Operating
System-Application compatibility
	I'm not going to
address this, but it is something to research and understand.


Define what components you need
You will need the
core and storage components.


If you have
components (particularly auxiliary components) from a previous
system, you may find you can use them with the new system.  Speakers,
printer, and monitors are all prime candidates.


Steps

CPU


Decide on CPU brand (typically
	Intel or AMD)
Decide on CPU model, which is
	dictated by your needs and budget
CPU will dictate motherboard
	socket type
Be sure to buy CPU in box set so
	it includes CPU fan & heat-sink.  Otherwise, you'll need to
	figure out the thermal dissipation needs and physical dimension
	limitations of the case in order to select an appropriate 3rd party
	CPU fan & heat-sink.  This can involve liquid cooling solutions.
	 I'm not covering thermal solutions in detail here.


Motherboard


Narrow search to motherboards with
	socket type that matches CPU.
Decide on motherboard form factor
	(ATX, Mini-ATX, Micro-ATX, Mini-ITX, etc.).  See Wikipedia.
Video on-board or discrete.  
	

If on-board, check if it has
	dedicated memory or borrows memory from main system.  If it borrows
	from the main system, you may want to increase your memory size. 
	Recommend using discrete if 3-D requirements exist.  You can go
	discrete later, but you'll have wasted money on the motherboard.
If discrete, ensure motherboard
	has enough high-end PCI-e slots for your needs. 
	



Audio on-board, discrete or
	external.

If on-board, check motherboard has
	suitable output ports for your needs.
If discrete, ensure motherboard
	has a slot for the audio card.


If external audio system will be
	used, make sure motherboard has ports to support it.
WiFi / Blue Tooth
While a few motherboards have these,
	they are generally considered inferior for connectivity and security
	on a non-mobile device like a desktop.  It's also easy to add a card
	or USB device to obtain them.  Also, when integrated on the
	motherboard, they are harder to upgrade later.



Outputs ports meet your needs
	(PS2, Parallel, Serial COM, USB, eSATA, S/PDIF, HDMI, Ethernet,
	etc.)
At this point, you search should
	be fairly narrow – compare prices, read reviews and compare
	ratings. 
	
Decide on motherboard vendor and
	model


Memory


Based on motherboard, find
	matching memory type.  DDR2 and DDR3 are the common types.  
	
There are 5 memory properties:  
	

DDR revision (currently they
	include DDR, DDR2, and DDR3)
Chip Classification (like
	DDR2-1333) where the number (1333) is the maximum clock speed (in
	MHz) the memory chips support, which is halved for real clock speed
	(666.5MHz).
Module Classification (like
	PC3-10666) where the number (10666) is the maximum transfer rate (in
	MB/s).  This is typically 8 times the first memory chip
	classification clock speed, so DDR400 transfers data at 3,200 MB/s. 
		
Timing (like 7-8-8-24) measures
	the time the memory chip delays doing something internally.
Voltage (like 1.5v)  
	



Note the memory properties are
	maximums.  Actual rates will be lower based on the motherboard. 
	Match the first 3 properties – DDR revision, chip classification
	and module classification.  DDR revision must match.  If you can't
	get an exact match on Chip and Module classifications, make sure the
	memory module is faster (higher numbers) than the motherboard.
If you plan to over-clock, you'll
	need to pay attention to all 5 properties, but I'm not going to
	cover over-clocking.
For more assurance, buy memory
	that's on the motherboard maker's certified list.
Recommend buying memory in higher
	capacities per module for future expansion.  If you have 4 memory
	module slots which can accept 1G, 2G, and 4G modules, opt for the 4G
	modules.
Recommend that all memory modules
	be the same size, optimally the same brand/model if possible.


Video Card


If using on-board video
	controller, you've already decided this.
If using discrete video card,
	narrow search to available motherboard slots.  
	
For example, if you only have one
	PCI-e 16x slot, narrow search to video cards that can use that slot.
	 Don't worry about AMD's CrossfireX or NVIDIA's SLI card linking
	because you don't have two slots. 
	
If you buy a high-end discrete
	card or cards, be sure to check the video card vendor's recommended
	power supply wattage and required power connector.  These cards
	often require a separate power connector from the power supply.


Internal Storage 


By internal
	storage, I mean storage devices that will be housed inside the
	computer case.
Most
	motherboards come with an on-board storage controller, typically
	SATA 2.  Some have an IDE controller for legacy support.  Server
	motherboards may have some version of SCSI or SAS (serial attached
	storage) controllers.
These
	on-board controllers are configured from within the BIOS or UEFI. 
	Depending on the motherboard's south bridge chipset, it may support
	a few RAID levels, usually levels 0 (striping) and 1 (mirroring).
Storage
	devices come in different physical sizes which require different
	sized bays - 5.25 inch, 3.5 inch, 2.5 inch, and 1.8 inch.  These
	refer the size of the storage medium, not the actual bay size.  The
	5.25 inch bays come in half-height versions, which are the standard
	for CD and DVD drives in todays' computers.  The 3.5 inch bays are
	usually used for floppy or Zip drives...more legacy equipment.  See
	Wikipedia.
Storage
	devices can vary significantly in storage capacity.  Often, the
	larger the storage capacity, the higher the latency in storing and
	retrieving data.  Cache on-board the disk can mitigate this latency,
	so larger cache sizes are preferred particularly for large capacity
	drives.  Cache sizes currently include 8MB, 16MB, 32MB and 64MB.
With rotating
	magnetic disks, the speed at which they rotate can also mitigate
	this latency.  Rotation speeds include 5400 rpm, 7200 rpm, and 10000
	rpm and 15000 rpm with each step in speed requiring more power and
	giving off more heat.
If you need
	more than 2 or 3 drives, you'll need to ensure your case has
	adequate physical space for them and that your power supply is sized
	appropriately.




Case & Power Supply


Some cases are bundled with a
	power supply, which might work great for average to low-end system
	configurations.
Based on motherboard form factor
	and internal storage requirements, pick out a computer case.  
	
Case features to consider:

Power supply location is always
	in rear, but can be on top or bottom of a tower configuration.  If
	the computer will sit on the floor, having the power supply on the
	bottom might turn it into a dust bunny haven.
Number and type of storage drive
	bays.
Removable and/or washable dust
	filters.
Lighting kits
Front panel ports and static
	suppression



The number and size of fans is
	limited by the case design.  Typically a case will come with one
	rear fan, but most offer front, side, or top vents where fans can be
	mounted. Fan sizes range from 25mm to 250mm, with popular sizes at
	80mm, 92mm, 120mm and 140mm.
Make sure power supply is sized
	correctly:

Physical dimensions fits in case
	(beware “slim” power supplies for smaller form factor cases).
Wattage output, which is driven by
	video cards and number of internal storage devices.
Connectors required by the
	motherboard, CPU fan, case fans, video card and internal storage
	devices.



Without a discrete video card and
	2-3 internal storage devices, 300-400 Watts power supplies are
	typical.  If getting a discrete video card, check on its power
	requirements.
Power supplies also have
	efficiency ratings under the "80 PLUS" certifications, which
	span from vanilla 80 PLUS, Bronze, Silver, Gold and Platinum.  See
	Wikipedia for more info.

