VMware ESXi and vSphere Cluster Management
How to Change Virtual Machine Memory Allocation in VMware Workstation Player
Learn how to increase or decrease RAM assigned to a VMware Workstation Player VM, choose a safe memory value, and verify the change.
A virtual machine (VM) is a software-defined computer that runs a guest operating system on a physical computer. The physical computer is the host, and its directly installed operating system is the host operating system.
VMware Workstation Player lets you configure how much of the host computer's physical RAM—random-access memory—is available to a particular VM while that VM is running. This configured amount is the VM's memory allocation.
When changing VM memory helps
A guest operating system needs RAM for its kernel, desktop environment, background services, and applications. When its allocation is too small, it may use paging, which means using disk storage as an extension of RAM. Disk storage is much slower than physical memory.
Too little guest memory can cause slow application launches, excessive disk activity, freezes, and generally poor responsiveness. Increasing the allocation can improve performance when guest memory usage is the actual bottleneck.
However, assigning excessive RAM can create memory pressure on the host. Memory pressure occurs when the host and its running programs demand more physical RAM than the computer can comfortably provide. The host may then page to disk, slowing the host, the VM, and other VMs.
Adding RAM will not fix every performance problem. CPU limits, slow virtual or physical storage, graphics workloads, network performance, and application-specific bottlenecks require different solutions.
Requirements before changing memory
- Save your work in the guest operating system.
- Shut down the guest operating system normally.
- Confirm that VMware Workstation Player shows the VM as powered off.
A powered-off VM has finished shutting down and is no longer executing. A suspended VM has a saved running state. Suspension is not the same as a full shutdown, and VMware may prevent hardware settings from being edited while the VM is suspended.
If the Memory control is unavailable, resume the VM if necessary and shut down the guest operating system rather than suspending it. Do not change the setting while the VM is running.
Open the virtual machine hardware settings
- Select the target VM in the VMware Workstation Player library.
- Open the Player menu.
- Choose Manage, then Virtual Machine Settings.
- Open the Hardware tab.
Virtual Machine Settings is the VMware interface for configuring virtual hardware such as memory, processors, disks, and networking.
Adjust the Memory device setting
- In the virtual hardware device list, select Memory.
- Use the memory input, slider, or available selection control to choose the desired RAM amount.
- Choose a value that is a multiple of 4 MB. For example, 2048 MB and 4096 MB are valid multiples.
- Save or confirm the hardware setting.
- Start the VM. The new allocation takes effect when the VM boots.
The interface may present memory as megabytes or gigabytes. If you need to convert units, 1 GB is commonly displayed as 1024 MB in computer memory settings. Follow the values and range offered by the installed VMware version.
Navigation summary: Select VM in library > Player > Manage > Virtual Machine Settings > Hardware > Memory
Choose an appropriate RAM amount
Begin with the guest operating system vendor's minimum memory requirement. That minimum is a bootability baseline: it may allow the operating system to install or start, but it is not necessarily a good performance target.
Then account for the guest desktop environment, intended applications, and expected workload. A VM used for a single lightweight task needs less memory than one used for development tools, browsers with many tabs, databases, or several applications at once.
Also reserve enough physical RAM for the host operating system, browsers, development tools, and other host applications. If other VMs will run at the same time, their memory demands must be considered together.
Host and VM memory limits
Historically, the documented per-VM limits were up to 64 GB on a 64-bit host and up to 8 GB on a 32-bit host.
These historical figures do not guarantee that every installed version offers the same range. Practical limits also depend on installed host RAM, the host operating system, VMware version, and the VM's compatibility settings. When a requested value is unavailable, verify the limits shown by the installed product version.
The total configured memory across VMs is not necessarily a single fixed Player-wide allocation limit. Nevertheless, all simultaneously running VMs must share the host's actual physical resources. Configuring large values for several VMs can overwhelm a host even when each individual value is accepted.
Example: improving a slow Windows 8.1 VM
- Review the guest operating system requirement and the applications used inside the VM.
- Check whether the host has sufficient unused physical memory.
- Shut down the guest and make sure the VM is powered off.
- Open Player > Manage > Virtual Machine Settings > Hardware > Memory.
- Increase the allocation to a suitable value in a 4 MB increment.
- Save the setting, start the VM, and confirm that the guest recognizes the new allocation.
This change is useful when the guest is constrained by RAM. It is not useful to keep increasing memory if the host begins paging or if CPU, storage, or another resource is the real bottleneck.
Example: meeting a Windows 10 64-bit baseline
If a new Windows 10 64-bit VM has less than 2 GB of RAM, use the operating system vendor's stated minimum as the minimum allocation target. Allocate at least 2 GB for that baseline, then add memory if the VM will run modern desktop applications or several programs.
Do not interpret the minimum as a universal recommended value. A guest that boots with the minimum may still perform poorly under a normal desktop workload.
Example: avoiding host slowdown
On a host with limited RAM, do not assign nearly all physical memory to one VM if you also need a browser, development tools, or other applications. Leave capacity for the host operating system and expected host workload.
If both the host and guest become slow after increasing the allocation, reduce the VM allocation or close other workloads. A smaller VM allocation that leaves the host responsive can provide better overall performance.
Confirm that the guest received the new memory
- Boot the VM after saving the setting.
- Open the guest operating system's system-information utility or task-management utility.
- Inspect the detected installed memory and, where available, the usable memory.
Exact verification steps vary by guest operating system. The guest may report a slightly different usable-memory figure because of hardware reservations or operating-system reporting conventions. Compare the reported value with the configured value, while allowing for those reservations.
If the expected value does not appear, power off the VM again, confirm that the setting was saved, and verify that you modified the correct VM.
Troubleshooting memory changes
The Memory setting cannot be edited
- Confirm that the VM is fully powered off, not running.
- If it is suspended, shut down the guest operating system normally and check the VM state again.
- Confirm that you opened the intended VM and its Virtual Machine Settings window.
- Check file permissions or ownership if the setting remains unavailable.
The desired memory amount cannot be selected
- Choose a value in a valid 4 MB increment.
- Check the available configuration range for the installed VMware version.
- Consider host architecture, VM compatibility, installed host RAM, and host operating-system limits.
- Use a lower value or upgrade the host environment if the workload genuinely requires more memory.
The VM remains slow after increasing RAM
- Inspect CPU, memory, and disk activity in both the host and guest.
- Reduce the allocation if the host is paging heavily or all applications have slowed.
- Increase memory only when guest usage indicates sustained memory pressure and the host has capacity.
- Investigate CPU, storage, graphics, network, and application-specific bottlenecks.
The guest does not show the expected value
- Make sure the VM was restarted after the setting change.
- Power it off and confirm the configured value in Virtual Machine Settings.
- Verify the guest's installed and usable memory values.
- Confirm that the correct VM was modified and account for reserved hardware memory.
Practical tuning checklist
- Check the guest vendor's minimum memory requirement.
- Estimate memory for the guest OS, desktop, applications, and workload.
- Reserve memory for the host OS and host applications.
- Account for other VMs that may run concurrently.
- Change the setting only while the VM is powered off.
- Use a 4 MB multiple and increase gradually.
- Boot the guest and verify detected memory.
- Observe both host and guest performance before making another change.
For the complete procedure, use the VM memory allocation guide as a reference when adjusting the setting.