Q: How do I check my computer memory?

A: Check How Much Memory You Have

If you are on a Windows machine, in File Explorer, you can choose This PC, right click, and choose Properties

Or, you can go to Settings > System >About

PC About Memory

For more detailed information about your motherboard and the memory installed, you can download and run Speccy from Piriform or CPU-Z from CPU-ID

If you are on a Macintosh, go to the Apple Menu, About this Mac… and it should show you the amount of memory you have and the OSX Version

About This Mac Memory\

For more information on the number of RAM Modules and their placement, you can go to System Report and look under Memory in the Hardware section

More detail:

Some machines, especially servers and workstations, can take multipple different types of memory, and these are mutually exclusive – that is, you cannot have two types of memory in the machine at once. Your purchased memory must match the existing memory type.

The best plan with Servers, Workstations and Mac Pro machines is to shut the machine down and pull out one or more memory modules, and take a photo of the memory with the labels showing clearly and email that photo to us.

The most common issues are between ECC Unbuffered, ECC Registered and Load Reduced memory. The software reports above may not specify which you have. There will be numbering on the labels that can tell us what type of memory it is.

ECC Unbuffered usually has E or EU, UR or UB on the label.
ECC Registered usually has R or Reg.
Load Reduced usually has LR,
occasionally only L which can be a problem because L is also used to designate Low Voltage. LP and VLP are used to designate low profile and very low profile DIMMs
Non-ECC RAM as is normally used in consumer and office machines is unbuffered by definition.
In addition, you may see numbering that can tell the speed, voltage and ranking of the memory.

There are two ways of designating memory, PC# and DDR# The speed numbers on PC# are in bits while on DDR# they are in Bytes, so the PC# numbers are 8x the DDR# numbers

PC3L-12800R 2R for example would be DDR3, Low voltage (1.35V), 1600 MT/s (12800 / 8), Registered, two Ranks

DDR4-2666U SR would be DDR4, 2666 MT/s. Unbuffered, Single Rank. Note that this doesn’t tell us whether it is ECC or non ECC – in the absence of any other marking that says E, ECC, or 72-bit, we assume that this is NON ECC memoryu

PC4L-21300LR QR would be DDR4 Low Voltage, 2666 MT/s (21300 / 8), Load Reduced, 4 Rank (Quad Rank)

A: Check if your memory is OK

Your machine does a Power On Self Test of memory when you start it up, so if your machine is running you are halfways there to knowing your RAM is OK. But if you are getting unexplained crashes, especially random shutdowns or freezes unrelated to any activity you are doing in software, then it is worth running an extended test on the memory. You would want to set the test to run several passes of memory testing, as random errors may not show up on one test run. The testing can take hours, you can set it up to run overnight.

If you have a Windows machine

You can use the freeware utility MemTest to make a bootable USB stick or CD-ROM to reboot the machine and run the Memtest routine from the bootable media

or there are free and paid versions from Passmark or TechPowerUp

If you have a Macintosh

You can use the freeware utility Rember to test memory or you can run the built in Apple Diagnostics or for old Macs the Apple Harware Test suite