> For the complete documentation index, see [llms.txt](https://docs.parallels.com/landing/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.parallels.com/landing/pdfm-ug/parallels-desktop-for-mac-27-users-guide/use-windows-on-your-mac/optimizing-performance/allocating-specific-amount-of-memory-to-windows.md).

# Allocating Specific Amount of Memory to Windows

Parallels Desktop is set to allocate a certain amount of your Mac's available RAM memory to Windows and the rest to macOS. If too much memory is allocated to Windows, macOS may slow down, which in turn can cause Windows applications to slow down because they're running on top of macOS. If, on the other hand, too much memory is allocated to macOS, then macOS applications may run well but Windows applications might slow down.

To optimize the performance of both Windows and macOS, set the memory allocated to Windows to be somewhere within the recommended range.

To set how much memory is allocated to Windows:

1. [Shut down Windows](/landing/pdfm-ug/parallels-desktop-for-mac-27-users-guide/use-windows-on-your-mac/getting-started/shutdown-and-suspend-windows.md).
2. Choose **Actions** > **Configure** > **Hardware** > **CPU & Memory**.
3. Move the memory slider to somewhere within the recommended range, indicated by the graphic under the slider (see above).

   If you use Windows applications that require lots of memory, like 3D or video production applications, it's best to set the memory allocation towards the high end of the range (move the slider to the right). If not, it's usually best to set it closer to the middle.

{% hint style="info" %}
**Note:** No matter how much memory (RAM) your Mac has, the maximum amount of memory that can be assigned to Windows is 8 GB. However, if you're using Parallels Desktop for Mac Pro/Business/Enterprise Edition, the maximum amount of memory that can be assigned to Windows is 128 GB.
{% endhint %}

If you change this setting and then you don't like how Windows is performing, then try a different setting.

{% hint style="info" %}
**Note:** If you want to prevent Virtual Machine Configuration from unauthorized changes, click the Lock icon at the bottom of the window. The next time someone wants to change the settings in any pane of Virtual Machine Configuration, an administrator's password will be required.
{% endhint %}


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