The following tips and information help you decide what type of memory to buy when upgrading your computer.

Determining the type of memory required

If you’re considering a memory upgrade, the first step is determining which memory is currently installed and what types of memory your motherboard supports.

  • Determining the type of memory required.
  • What to look for in memory.
  • Before purchasing memory.
  • Installing the memory.

Use a third-party tool or service

One option is to use a third-party software utility or online service that provides details about the components in your computer. These utilities can scan your computer and give a detailed report of all installed hardware, including memory. For example, the Crucial System Scanner is a free utility that scans your computer and gives details about installed memory and any available memory slots.

  • How to download an app, file, or program from the Internet.
  • Where are the files I downloaded using my web browser?

Documentation

The best method of determining the memory (RAM) to use with your computer is through the computer or motherboard manufacturer documentation. If you do not have your product documentation, you can find it online through the computer manufacturer or the motherboard manufacturer website.

  • How to find the type of computer motherboard.

For example, your motherboard documentation may list something similar to the example below.

Supports DDR4 2666/2400/2133 SDRAM. Supports up to 4 non-ECC unbuffered DIMMs. Up to 8 GB per DIMM, with a maximum total memory size of up to 32 GB.

The example above shows that the motherboard supports DDR4 SDRAM DIMM at speeds of 2666, 2400, and 2133 MHz.

Visually examine the memory

You can also open the computer. Taking precautions not to cause ESD (electrostatic discharge), remove one of the memory sticks and physically examine the memory for any identifying stickers or printed labels.

  • How to open a computer case.

What to look for in memory

Below is a short list of what to look for when determining your computer’s memory needs.

Memory type

What type of memory does the computer use? Some examples of the different memory types include DDR-SDRAM, DDR2-SDRAM, DDR3-SDRAM, DDR4-SDRAM, DIMM, DRAM, EDO, FPM, SDRAM, LIMM, RDRAM (RAMBUS), RIMM, SIMM, and SODIMM. Today’s computers usually use a variant of DIMM/SDRAM memory.

Amount of pins

How many pins does the computer accept? 72-pin, 30-pin, 168-pin, 184-pin, or 240-pin? The answer depends on the type of memory.

Speed of memory

There are two primary measurements of memory speed.

  • The “speed” of memory generally refers to how often the memory can read or change its data per second. This speed is measured in MHz and strongly affects the overall performance of your CPU.
  • Latency is the (very short) time it takes for the memory to respond to information requests, access data stored in memory, and send that data to the CPU. Latency is measured in nanoseconds (ns).

Although latency is an important metric, differences in latency are relatively minor in compatible RAM modules. When deciding what memory to use in your computer, the speed measured in MHz is generally the more important number to consider.

Error-checking

ECC (error-correcting code) memory is used in servers and professional workstation computers. It sacrifices some of its speed to provide error protection by verifying there are no errors whenever data is modified in RAM.

If you install memory sticks of varying speed ratings in your computer, the lower speed is used, and you don’t receive the potential benefit of the faster module’s speed. When possible, use RAM modules of equal speed. Ideally, you want all RAM installed in your computer to be identical.

Errors may naturally occur in RAM because of electromagnetic interference or hardware faults. As a result, bits can become “flipped” in RAM; some bits that should be set to 1 are set to 0, or vice versa. These errors are usually not fatal for casual applications like video games or web browsing. For example, if a single pixel in the background of a video game is the wrong value, you might not notice or care. However, ECC is a necessary feature for professional applications that require a high degree of accuracy, such as financial transactions or scientific calculations. ECC doesn’t prevent errors entirely, but it reduces their probability to nearly zero.

Not all motherboards support ECC, and those that support ECC are usually more expensive. The ECC RAM modules are also more expensive than non-ECC RAM of equivalent speed. If you’re unsure if you need ECC, you probably don’t. Building a computer without ECC support usually means getting more bang for your buck in terms of your computer’s performance.

Voltage

What are the voltage requirements? Make sure you determine the voltage requirements of the memory (e.g., 1.5v, 1.8v, or 2.5v).

Contact material

The contact material on the memory is also important when buying computer memory. The contact area is coated in either gold or tin and should match the material of the memory slots. Mismatching the memory and memory slot contact material can cause corrosion.

Proprietary

Finally, is the memory in your computer proprietary? If not, is there memory your computer manufacturer recommends?

  • Computer memory manufacturers.

Other terms

See our memory terms page if there’s any other jargon confusing you.

If you have a more recent computer (made in the last five years), this should not be a concern.

Before purchasing memory

Ensure the computer has the available memory slots for the memory you are installing. For example, if you’re installing an additional 8 GB of memory in the computer and plan on using two 4 GB memory sticks, make sure you have two available slots. If you do not have available slots, you can remove pre-existing memory and install new memory. However, any memory removed is subtracted from your total. Below is an example of a possible scenario.

A computer has 4 GB of memory from four different 1 GB sticks of RAM, and has no more available slots. If you want to upgrade to 8 GB, the four 1 GB sticks would need to be replaced with four 2 GB sticks. Alternatively, two 1 GB sticks could be replaced by two 4 GB sticks.

  • How to find how many memory slots are in a computer.

Installing the memory

When you’re ready to install the memory you purchased, follow the steps and precautions in our guide below.

When dealing with memory, 1 GB = 1,024 MB

  • How to install computer memory (RAM).
  • Computer memory buying tips.
  • How to find how much RAM is installed on a computer.
  • How to install computer hardware.
  • See our memory definition for further information and related links.
  • Memory (RAM) help and support.