COMPTIA Chapter 3.6 Memory Installation

You have an older computer that has four DDR2 memory slots. Currently, there are two 512-MB memory modules installed. You check the motherboard documentation and find that the system has a 4-GB memory limitation. You want to add more memory to this system. What is the maximum total amount of usable RAM you can have in this system by adding new memory modules (and without replacing the existing memory modules)? Answer -3 GB -3.5 GB -2 GB -4.5 GB -1.5 GB -4 GB

-3 GB

You want to build a new system that supports 16 GB of memory. Which of the following is the MOST important consideration when building the computer? Answer -CAS latency -DDR3 memory -64-bit processor -ECC memory

-64-bit processor To use over 4 GB of memory, you need a 64-bit processor and a 64-bit operating system. 32-bit processors support up to (or slightly below) 4 GB of memory. While 16 GB of memory will likely use DDR2, DDR3, or DDR4, this is not a requirement.

You work as the IT administrator for a small corporate network. Sam, an employee in the support department, wants to run a virtual machine on his computer for troubleshooting customer issues, and he needs a very stable computer from which to work. You need to decide whether to install buffered or non-buffered RAM in his computer. Which of the following BEST describes the reason to choose buffered instead of unbuffered memory for this new computer? Answer -Buffered memory reduces the load on the memory controller, but due to the extra clock cycle, is less stable. -Buffered memory reduces the load on the memory controller and allows the system to be more stable. -Buffered memory is faster and less expensive. -Buffered memory increases the load on the memory controller, but is faster and more stable.

-Buffered memory reduces the load on the memory controller and allows the system to be more stable.

With a memory module read request, there is a delay between the time of the data request and the time the data is available for output from the memory module. What is this delay called? Answer -Clock cycle parity -Frequency -CAS latency -Capacity

-CAS latency

You are in a carpeted office lighted by fluorescent bulbs. You are preparing to add memory modules to a user's computer. The user has already unpacked the memory modules and stacked them on top of an old, unused CRT monitor. What is the greatest threat to these memory modules in this environment? Answer -Electromagnetic interference (EMI) from the fluorescent lights. -High-voltage discharge from the CRT monitor. -The magnetic field around the CRT monitor. -Electrostatic discharge (ESD).

-Electrostatic discharge (ESD).

Which of the following is the most common method for removing RAM from a motherboard? Answer -Move the tabs holding the RAM out of the way; then pull straight up to remove the RAM. -Remove the screw from the one side; then pull straight up to remove the RAM. -Tip the RAM module at a 45-degree angle while pulling on it. -Pull the RAM module up from one corner and then twist to release the other corner.

-Move the tabs holding the RAM out of the way; then pull straight up to remove the RAM.

You have an existing system that has a single DDR3 memory module installed. You would like to add more memory to the three remaining empty memory slots. Which of the following steps should you take to make sure that you get the right memory for the system? (Select two.) Answer -Purchase the slowest modules to ensure compatibility. -Update the BIOS and then purchase the newest memory modules available. -Purchase the fastest modules possible. -Purchase additional modules that are the same as what is currently installed. -Check the motherboard documentation to find which modules are supported

-Purchase additional modules that are the same as what is currently installed. -Check the motherboard documentation to find which modules are supported

Which of the following statements is true regarding single- and double-sided memory? Answer -Double-sided RAM always has modules on both sides of the circuit board. -Single-sided memory uses half the number of memory modules as double-sided memory of the same capacity. -Single-sided RAM can be organized into two banks. -Double-sided RAM allows the computer to access all of the memory.

-Single-sided memory uses half the number of memory modules as double-sided memory of the same capacity.

You have just upgraded the memory in one of your network servers by adding two 4-GB ECC memory cards. Before purchasing the new memory, you made sure that the modules fit in the memory slots (packaging) and the speed (memory frequency) was supported by the memory controller. What did you forget to check that would significantly impact the memory checking of your new ECC memory cards? Answer -Whether or not the new memory modules are buffered. -Whether or not the existing memory modules support parity RAM. -Whether or not the existing memory modules support ECC. -Whether or not the new memory modules are single- or double-sided.

-Whether or not the existing memory modules support ECC.

You are trying to push a memory module into a memory slot, but it is not seating properly. What is the MOST likely issue? Answer -You are trying to install the memory module backwards in the memory slot. -You are trying to install a single-sided memory module in a double-sided slot. -You need to push down the slot tabs and move them back. -You need to clear debris from the memory slot.

-You are trying to install the memory module backwards in the memory slot.

Buffered memory

A space in memory that holds memory addresses or data before it is transferred to the memory controller. It is also called registered memory.

Error correcting code

A type of memory that detects and corrects common internal data corruption. It is also called parity memory.

Column address strobe or signal (CAS) latency

Another factor that affects the performance of memory is the latency associated with accessing data in RAM. With a read request, the CAS latency (CL) is a delay between the time the data is requested and the time that the data is available on the module's output pins.

Frequency

For optimal performance, you should match the memory frequency (sometimes called the speed) with the frequency supported by the system bus/memory controller.

Single-sided/double-sided RAM

Single-sided RAM has memory modules that are organized into a single logical bank; double-sided RAM has modules organized into two banks.

Capacity

The capacity (sometimes called the size) refers to the storage capacity of the memory module (e.g., 256 MB, 512 MB, 1 GB). The total capacity of memory that you can install in a system is limited by:

Packaging (memory form)

When you are purchasing RAM for a system, the most important consideration is the packaging, also called memory form. The packaging controls both the physical size of the memory module and the memory standard (e.g., DDR2, DDR3, DDR4).

Parity RAM

a type of memory that checks for common kinds of internal data corruption. It does not correct internal data corruption. Non-parity memory does not perform error checking. *no longer used in today systems. Most systems today use ECC RAM over party when needed.

Buffered (registered)

holds memory addresses or data in a buffer before it is transferred to the memory controller.