IHW H6

• Random-access memory (RAM)


  Type of computer memory
• Read-only memory (ROM)


  Type of computer memory
• RAM vs ROM


  • Difference between them is shown in Figure 6.1
• Types of RAM


  • Dynamic RAM (DRAM)
  • Static RAM (SRAM)
• DRAM


  Less expensive but slower than SRAM, requires refreshing to maintain data
• SRAM


  Also known as cache memory, holds frequently used data for faster access
• Accessing information from cache is much faster than accessing it from DRAM or hard drive
• It takes roughly a million times longer to access information from the hard drive than it does to access information from DRAM or cache
• Memory is one of the most critical things on the motherboard that can easily be upgraded
• Memory physical packaging


  • Dual in-line package (DIP) chip
  • Single in-line memory module (SIMM)
  • Dual in-line memory module (DIMM)
  • Small outline DIMM (SODIMM)
• Planning a memory installation

  1. Refer to system/motherboard documentation

  2. Determine supported features

  3. Determine amount of memory needed

  4. Determine memory modules needed

  5. Research prices and purchase
• Memory module types


  • Synchronous DRAM (SDRAM)
  • Double data rate (DDR)
  • DDR2
  • DDR3
  • DDR3L
  • DDR4
  • DDR4L
• Chipset


  Determines what faster memory chips the motherboard supports
• DDR, DDR2, DDR3, and DDR4 memory modules are physically the same size despite different pin counts
• DIMM models


  • PC2-9200
  • PC2-9600
  • PC3-6400
  • PC3-8500
  • PC3-10600
  • PC3-12800
  • PC3-16000
  • PC3-17000
  • PC4-1866
  • PC4-2400
  • PC4-2666
  • PC4-3000
  • PC4-25600
• Memory features


  • Parity
  • Non-parity
  • Error correcting code (ECC)
  • Unbuffered memory
  • Buffered memory (registered memory)
  • Serial presence detect (SPD)
  • Single-sided memory
  • Double-sided memory
  • Dual-voltage memory
  • Extreme memory profile (XMP)
• Registered memory also uses ECC technology
• Most memory modules today are non-parity because the memory controller circuitry provides error correction
• Minimum operating system starting memory recommendations

  • Windows 7: 1 GB
  • Windows 8/10: 1 GB (32-bit)/2 GB (64-bit)
  • macOS Mavericks/Yosemite/El Capitan/Sierra/High Sierra/Mojave: 2 GB
  • Linux: Depending on version, from 64 MB
• Even if the motherboard allows more memory, the operating system may have limitations
• The more memory you need for tasks like gaming or photo/video/sound manipulation, the more memory you will need
• Minimum operating system starting memory recommendations

  • Windows 7: 1 GB
  • Windows 8/10: 1 GB (32-bit)/2 GB (64-bit)
  • macOS Mavericks/Yosemite/El Capitan/Sierra/High Sierra/Mojave: 2 GB
  • Linux: Depending on the version, from 64 MB
• When upgrading memory


  1. Determine how much memory you are starting with

  2. Determine how many motherboard RAM slots are currently being used, and if there are any slots free

  3. Determine the maximum amount of memory your motherboard supports
• Even if the motherboard allows more memory, your operating system has limitations
• Windows 7/8/10 memory limits

  • Windows 7 Starter edition: 2 GB
  • Windows 7 Home Basic: 4 GB (32-bit), 8 GB (64-bit)
  • Windows 7 Home Premium: 4 GB (32-bit), 16 GB (64-bit)
  • Windows 7 Business/Professional/Enterprise/Ultimate: 4 GB (32-bit), 192 GB (64-bit)
  • Windows 8: 4 GB (32-bit), 128 GB (64-bit)
  • Windows 8 Professional/Enterprise: 4 GB (32-bit), 512 GB (64-bit)
  • Windows 10 Home: 4 GB (32-bit), 128 GB (64-bit)
  • Windows 10 Pro/Enterprise: 4 GB (32-bit), 2 TB (64-bit)
• To see the amount of installed memory in Windows

  1. In Windows 7, right-click Computer > Properties

  2. In Windows 8/10, right-click (or tap and hold briefly) This PC > Properties

  3. Or, in any version of Windows, access the System Information window from a command prompt by typing msinfo32 and pressing Enter
• Each motherboard supports a maximum amount of memory
• Dual-channel memory


  The motherboard memory controller chip handles processing of memory requests more efficiently by handling two memory paths simultaneously
• Dual-channeling increases a system's performance, but only if the memory modules match exactly
• Motherboard manufacturers frequently require that the memory modules match in all respects - manufacturer, timing, and capacity - in order to support dual-channeling
• Do not install over 4 GB on a computer with a 32-bit operating system such as 32-bit Windows
• To plan for the correct amount of memory


  Refer to the motherboard documentation
• Possible solutions for installing 2 GB of RAM on a motherboard with four memory slots

  • Four 512 MB DIMMs installed in DIMM1, DIMM2, DIMM3, and DIMM4 slots (dual-channeling)
  • Two 1 GB DIMMs installed in DIMM1 and DIMM2 slots (dual-channeling)
  • Two 1 GB DIMMs installed in DIMM1 and DIMM3 slots (not dual-channeling)
  • One 2 GB DIMM installed in DIMM1 (not dual-channeling)
• Many newer motherboards and server motherboards support triple-channel memory or quadruple-channel memory
• Memory speed


  Can be represented as MHz or the PC rating, with the higher the number meaning the faster the speed of the module
• Sample DIMM advertisements


  • 2 GB DDR3 PC3-10600 • CL=9•UNBUFFERED•NONECC•DDR3-1333•1.35 V•256 Meg×64
  • 2 GB DDR3 PC3-12800E•CL=11•REGISTERED•ECC•DDR3-1600•1.35 V•256 Meg×72
  • 2 GB kit (1 GB×2) DDR3 PC3-10600•CL=9 • REGISTERED • ECC • DDR3-1333 • 1.5 V • 128 Meg×72
  • 2 GB DDR2 PC2-5300FB • CL=5 • FULLY BUFFERED • ECC • DDR2-667 • 1.8 V • 256 Meg×72
• CL (column address strobe [CAS] latency)


  The amount of time (based on clock cycles) that passes before the processor moves on to the next memory address
• The lower the CL rating, the faster the memory
• Buying memory that is faster than the motherboard allows is like taking a race car on a one-lane unpaved road
• Usually, you can mix CL memory modules, but the system will run at the slower memory speed