The quickest way to check maximum RAM capacity in Windows 11 is to open Terminal (right-click Start > Terminal) and run Get-CimInstance Win32_PhysicalMemoryArray | Select-Object MaxCapacityEx, MemoryDevices. MaxCapacityEx is in kilobytes, so divide by 1,048,576 to get GB; MemoryDevices is your number of RAM slots. Then double-check against your PC maker’s specifications and your processor’s limit, since the BIOS-reported number isn’t always accurate.
Below is a full walkthrough for Windows 11, including how to see free slots, which RAM type you need, and the memory limits for each Windows 11 edition.
Check what’s installed now
- Press Ctrl + Shift + Esc to open Task Manager.
- Click Performance (the graph icon on the left) and choose Memory.
- Note the total RAM, Speed, Slots used, and Form factor.
If Slots used shows something like “2 of 2,” every slot is full, and upgrading means replacing sticks rather than adding them.
Find the maximum with Terminal or PowerShell
- Right-click the Start button and choose Terminal (or search for PowerShell).
- Run:
Get-CimInstance Win32_PhysicalMemoryArray | Select-Object MaxCapacityEx, MemoryDevices - Convert MaxCapacityEx to GB: divide by 1,048,576. For example, 134217728 is 128 GB.
The older wmic command
On many PCs you can still run wmic memphysical get maxcapacity, memorydevices in Command Prompt. Microsoft is removing WMIC from Windows 11, though, so newer installations may report that the command isn’t recognized. The PowerShell command above gives the same information.
Find out which RAM type you need
In Terminal, run:
Get-CimInstance Win32_PhysicalMemory | Select-Object Manufacturer, PartNumber, Capacity, Speed, SMBIOSMemoryType
The part number is the most useful detail: search for it to see the exact module type. As a rule, SMBIOSMemoryType 26 means DDR4 and 34 means DDR5. Your new RAM must be the same type and form factor (DIMM for desktops, SODIMM for laptops).
Confirm with your PC maker and CPU specs
- Go to Settings > System > About to see your device name and processor. For the exact model, run
msinfo32and check System Model and BaseBoard Product. - Look up that model on the manufacturer’s support site and find the memory specifications.
- Look up your processor on Intel’s or AMD’s website for its maximum memory size.
Your usable maximum is the lowest of the motherboard limit, CPU limit, and Windows limit.
Windows 11 memory limits by edition
| Edition | Maximum RAM |
|---|---|
| Windows 11 Home | 128 GB |
| Windows 11 Pro and Education | 2 TB |
| Windows 11 Pro for Workstations and Enterprise | 6 TB |
Windows 11 is 64-bit only, so the 4 GB limit of 32-bit Windows doesn’t apply. For most home PCs, the hardware limit is far lower than the Windows limit.
Example: working out an upgrade
Say Terminal reports a 64 GB maximum and 2 slots, Task Manager shows “2 of 2” with 8 GB installed, and your CPU supports 96 GB. Your limit is 64 GB (the motherboard), so the biggest upgrade is two 32 GB modules replacing the two 4 GB sticks. If the manufacturer’s spec says 32 GB maximum instead, trust that number and buy two 16 GB modules.
Tips before you buy RAM
- Buy matched kits (two identical sticks) for dual-channel performance.
- Check whether your laptop has soldered memory. If it does, only the remaining slot can be upgraded.
- Update the BIOS or UEFI before installing larger modules.
- Ground yourself and turn the PC off and unplug it before opening the case.
If Windows 11 doesn’t show all your RAM
- Check that each stick clicks fully into its slot.
- Run
msconfig, go to Boot > Advanced options, and clear Maximum memory. - Some memory is reserved for integrated graphics, shown as “Hardware reserved” in Task Manager.
- Test the RAM with Windows Memory Diagnostic (search Start for it).
Related: How to check RAM in Windows 11.
Related: How to check maximum RAM capacity in Windows 10.
Related: Check your RAM manufacturer in Windows 10.
Related: Find your computer specs in Windows 11.
Frequently asked questions
How much RAM can Windows 11 Home use?
Up to 128 GB.
How many RAM slots does my PC have?
Task Manager’s Memory page shows the total slots in Slots used, and MemoryDevices in the Terminal command gives the same count.
Is 16 GB enough for Windows 11?
For most people, yes. 8 GB works for basic use, and 32 GB helps with heavy multitasking, video editing, and some games.
Can I mix RAM sizes?
Often yes, but matched pairs run best. Mixed sticks may run at the slower speed or in a reduced dual-channel mode.
Kermit Matthews is a freelance writer based in Philadelphia, Pennsylvania with more than a decade of experience writing technology guides. He has a Bachelor’s and Master’s degree in Computer Science and has spent much of his professional career in IT management.
He specializes in writing content about iPhones, Android devices, Microsoft Office, and many other popular applications and devices.