Mr. Fixit's PC Upgrade and Repair
SYSTEM MEMORY
continued
Before you begin, strap on an Electrostatic wrist band around your wrist and the other end, using a 1-mega ohm resistor in series,
connected to the chassis. The strap when properly used will prevent any static build up and in the event you come in contact with a
power source, you will not be electrocuted through the strap. The ESD strap can be purchased at any electronics/computer store. You
can use a bare copper wire wrapped around the wrist and connect the other end through a 1-mega ohm resistor as alternative.

Follow these steps: (Watch Video)
  1. Shut down the computer, unplug it, and wait 15 minutes before opening the case. Note that some computers have a
    disconnect switch in the back next to the power cord as an alternative.
  2. Open the left side panel according to the documentation that came with the computer. They're usually either thumb
    screws or phillip screws.
  3. Connect the wrist strap to the metal chassis (frame). Be sure the strap is tight around the wrist.
  4. Move any obstructions out of the way of the memory modules/sockets. If cables must be detached, be sure to mark
    where they go.
  5. (If an empty slot is available, skip to next step) Push the ejector tabs on each end of the module gently, fully releasing
    the module, and grab the edges lifting the module straight up being sure not to touch the IC's or the contacts. Note the
    key notch locations. These ensure correct orientation when inserted.
  6. Make sure the key notches match the socket for proper insertion and the ejector tabs are flipped down. Holding the
    edges of the module, insert straight down with even pressure at both ends until the tabs fully latch on to the module. DO
    NOT USE EXCESSIVE FORCE!
  7. Reconnect any cable(s) that were detached.
  8. Replace the cover and reconnect the power. A slight 'pop' noise may be heard when connecting the power cord, this is
    normal.
  9. Turn on the computer.

Note: When using Multi-Channel, matching sockets may have the same color. Refer to the computer's documentation for
more information.

After turning on the computer, you may need to enter BIOS to allow the memory update to be saved. Newer motherboards
do this automatically. To be sure the newly installed memory is working properly, run a memory diagnostic program. Some
motherboards have built-in memory testers separate from the Power On Self Test (POST) protocol that all computers use
when turned on. Third-party softwares have extensive tests to ensure the memory modules are working properly.
Memory Modules
The key notch on the module must
line up with the notch on the socket
Memory Module Comparison
There seems to be some confusion about 'Dual-Channel' memory. When someone describes the memory module as "Dual-Channel" or some other
multi-channel type memory, ignore them. Multi-Channel refers to the connection between the memory controller and the modules, not the memory modules
themselves.
The memory controller, located in the North Bridge, is neAR the CPU and the System Memory. The memory controller
regulates data flow between the CPU, system memory, and the rest of the system. The memory controller determines the
type of modules, speed of the modules, the maximum size of each individual memory module, and the overall memory
capacity of the system. Previous motherboards used a single channel that was 64-bits (8 bytes) in width. Running intensive
memory hog programs, often caused 'bottlenecks' that hindered system performance because the memory controller
couldn't keep up with the CPU. To help improve system memory performance, newer motherboards started to use a new
technology called Multi-Channel. The 'Channel' refers to the link between the memory controller and the memory modules.
To minimize the effects, additional channels were added to increase data flow. The more channels, the more data that can
be moved. For every Channel that is added, the bandwidth is increased by 64-bits.
Dual-Channel has 2 64-bit channels increasing the bandwidth to 128-bits. Triple-Channel is 192-bits wide
(64 x 3) and the newest, Quad-Channel, is 256-bits wide (64 x 4). To better understand how this works,
lets assume the memory is running at 1,000 MT/s, which would be 8,000MB/s on a single channel.
Dual-Channel would increase the throughput to 16,000MB/s (8,000MB per channel) because the
bandwidth went from 64-bit to 128-bit. This is the benefit of having a multi-channel motherboard. To use
this technology, the motherboard must support. Dual, Triple, or Quad Channel. It's recommended the
paired memory modules match in capacity, type, and manufacture. Also make sure the paired modules
have the same number of chips on both sides. This ensures both modules can access memory at the
same time. A module with more/less chips may slow the system due to a different addressing scheme
comapared to its paired module.
When buying memory for use in a multi channel system, look for kits for the
specific channel.  When memory is sold in kits, like this one, they are not
referring to the memory type at all, but rather a guarantee by the manufacture
that the modules are identical in every aspect to work in a multi channel system.
Kits are available in 2GB,  4GB, 12GB, and 16GB for Dual, Triple, and Quad
channel systems depending on the amount of memory you are installing.

Let's assume your PC supports Triple Channel, has 3 memory slots, supports
maximum capacity of 12GB of DDR3-1600. You could buy a 12GB kit like this
one. The kit would contain (3) 4GB DDR3-1600 modules that the manufacture
guarantees these are identical modules. These modules will work in ANY PC
that supports the memory type, including non multi-channel PCs.

Be sure to read the documentation that came with your PC or the motherboard
to determine which sockets are paired. Not all motherboard manufactures follow
the same rules.
You may also notice a Column Address Strobe Latency (a.k.a CL or CAS) when
looking at memory specifications. On SDRAMs, the CL refers to the number of
Clock cycles that will pass before the module can respond to the memory controller’
s request. Starting with SDR modules, this latency was 2 clock cycles or CL2 for a
PC100 module, which measures 20 nanoseconds. At 100MHz, one clock cycle is 10
nanoseconds. As the clock speeds increase the clock cycle becomes shorter but
the CL increases. The fastest known memory is the DDR3-2000. At 1,000MHz, a
single clock cycle is 1 nanosecond and with a CL7 module, the response time is 7
nanoseconds. When buying memory, use modules with the lowest CL of the
supported memory type. Be advised that because the new module is 1600MHz
even though the motherboard is limited to 1333MHz, the system will still operate at
1333MHz and not be any faster. Look up the motherboard to see the fastest
memory clock speed that is supported and find that type with the lowest CL.
Memory modules (including motherboards) listing the speed with an (OC) next to it,
ignore that speed. OC refers to Over Clocking the system which occurs under
certain conditions that are not recommended. To over clock the system is to operate
beyond the limits and should only be done by individuals with the full understanding
of the risks involved.
Identifying the modules can be done in different ways. You can visit your PC manufacture’s
website and look up your model. Some PCs will advertise on the front as ‘upgradaeble to **GB
DDR###'. You can visit a memory retailer’s website and enter your brand and model in the
memory configuration. These will list the supported memory for your system and sometimes
indicate your motherboards maximum memory capacity. You can search your motherboard online
by it’s model # or it’s part # listed on the board, but the print may be too small. The last ditch
effort would be the removal of a module as shown here. Use caution when removing and
handling the modules, they are sensitive to static electricity. Do not touch anything on the
module or the electrical contacts, only handle them by the edges as I have demonstrated in other
videos. The tag on the module will give the modules capacity, type, the Data transfer rate in
MB/s (model), and sometimes the CAS Latency.
Finally, As I have mentioned several times, the maximum memory you can install will depend on two things; the motherboard’s supported
capacity and the Operating System installed. Motherboards are available that can support a Terabyte (1TB) of memory, but those are
only found in Servers. Some manufactured Home PC's motherboard will support 16GB as long as Windows Vista's or Windows 7's
Home Premium 64-bit edition is installed. Both Windows Vista’s and Windows 7’s Home Basic 64-bit editions support 8GB of memory.
All Windows XP 64-bit versions supported 128GB of memory. As for the 32-bit versions, none of them support more than 4GB, starter
editions support even less. To access above the 16GB boundary, you will need a motherboard that supports the capacity and Vista’s
Business, Windows 7’s Professional 64-bit editions or higher installed.
Installing Memory Upgrades

When upgrading the memory, you have 2 options: 1) you can add memory to a vacant slot or 2) remove an existing module to add the new one. This mainly
depends on how the motherboard was designed and the amount of memory that's already installed. Some motherboards have only 2 slots while others have
3 or more. If the motherboard has 2 memory slots and 2GB of memory installed, then the memory can be configure in 1 of 2 ways: 1) 2GB module in one slot
and the other vacant or 2) 1GB module in each slot. So if there is a vacant slot you can just add another module but if they're all full, at least one of the
modules would have to be removed to install the upgrade. Memory size limits depend on the version of Windows installed on the computer.