What to know about common memory specifications

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Crucial FAQ: What to know about common memory specifications


There are many words and acronyms associated with computers and servers that can be confusing. If you’re trying to upgrade your system and a slow computer has pushed your frustration to the limit, the last thing you want is to get slowed down further while trying to figure out what specific memory and storage tech terms mean. So without further ado, here are some frequently asked questions to help you learn more and find the best possible upgrade.


Memory (RAM) FAQs


Is it memory, RAM, or DRAM?

These three terms are often used interchangeably. ‘RAM’ stands for random access memory and ‘DRAM’ stands for dynamic random access memory.


What is a memory form factor?

A form factor is the physical form, or physical dimensions, of the module. UDIMM, or unbuffered dual in-line memory module, is the most common form factor of memory that desktops use. Laptops or other small systems use SODIMMs, or small outline DIMM, which have fewer pins (the gold edges on the bottom of the module) and are physically shorter than UDIMMs. Servers use a variety of different standards in addition to form factors, depending on how the server is used (RDIMM, LRDIMM, FBDIMM, ECC UDIMM, ECC SODIMM, NVDIMM, etc.).


What do you mean by “total capacity”?

The total capacity is the total memory the module or kit of modules provides in gigabytes (GB). More GBs of RAM are better because your system can quickly run and use more active data.


What is memory speed?

The amount of data that can be transferred from the memory to the CPU in a given amount of time. Speed is measured in megatransfers per second (MT/s), and in general, more speed is better.


Why is voltage important?

Voltage is how much power the module consumes. Higher voltages mean the system uses more energy and can also lead to higher system temperatures, which can negatively affect your system’s health.


What is bandwidth?

The total amount of data – not just speed – the module is able to process at once. The higher the bandwidth, the better.


What is latency?

The time delay between when a command (action) is entered and executed. In general, the lower the latency, the better. There are three numbers in the latency description – a DDR4 module with 16-17-17 latency has a CAS latency timing of 16, a tRCD timing of 17, and a tRP timing of 17. Although CAS latency ratings are the most common latency rating, it’s best measured in nanoseconds – what’s called true latency.


What’s the difference between buffered and unbuffered memory?

Buffered, also known as registered, memory is designed for server applications and has a safeguard, or intermediary, between the module and data to lighten the electrical load and ensure data integrity (i.e. it verifies that each piece of information sent to the memory is correct).


What’s the importance of memory technology and what does it mean?

A module’s memory technology must match your system’s memory technology to be compatible. Memory is available in several generations of technology, such as DDR, DDR2, DDR3, and DDR4. In addition, “upgrading your memory” usually refers to adding more GBs of RAM to the system – it doesn’t mean adding DDR4 memory to a DDR3 system because the modules are physically different from one memory technology to the next and won’t fit in the memory slot. To verify compatibility in just a few clicks, use our System Scanner or Crucial® Advisor™ tool.


How does component configuration affect the memory?

This is also known as the memory rank, which indicates how the chips (the black components on the module) are engineered to process data. A higher numbered component configuration means the module is able to handle more data for more intense workloads, but some systems have a limit on how many ranks they’re compatible with.


What does error-correcting code (ECC) do?

This adds an extra level of data integrity that’s preferred for some server and workstation applications. Most desktop and laptop memory modules don’t need ECC.



Crucial. The memory and storage experts.™

Memory and storage are crucial – your system won’t work without them. Every time you press the power button, load apps, save documents, type, or move your mouse, you’re using memory and storage. When it comes to these components, four factors are crucial: expertise, compatibility, reliability, and commitment. You need all four. As a brand of Micron, we’re part of one of the largest memory manufacturers in the world and we provide the same caliber of components that get pre-built into new computers. We live and breathe memory and storage, and we’re here to transform your system’s performance.