vmware-vmx double memory usage

[jlaundry]

Hello,

Currently, when trying to run Windows VMs on Fusion 13.5, I've noticed that the vmware-vmx processes in Activity Monitor show roughly double the Memory that was assigned to each VM - i.e., if I create a new Windows 11 VM and assign 4GB RAM, vmware-vmx shows ~8.05GB in Activity Monitor.

I've found that there have been various threads over the years talking about this, but none of these threads seem to have been 'resolved'. The trick of downgrading the Compatibility level to version 19 still seems to 'work' (in that Activity Monitor shows a realistic value) for Linux VMs.

• https://communities.vmware.com/t5/VMware-Fusion-Discussions/VM-s-using-double-RAM-then-assigned/m-p/...
• https://communities.vmware.com/t5/VMware-Fusion-Discussions/Memory-Usage-Doubled/m-p/2839970/
• https://communities.vmware.com/t5/VMware-Fusion-Discussions/Fusion-12-2-1-Memory-Doubles-on-Monteray...

I can also see that macOS is being reasonably smart about compressing memory: if I stop using the VMs for a few minutes, and then look at the Real Memory column in Activity Monitor and the RSS from `ps aux | grep vmware-vmx`, it looks like the Real memory of each process broadly aligns to what's reported by the guest OS.

But, if I go back to using the VMs, the Compressed Memory deflates, and Real jumps back up again: with 4GB assigned to the VM and the guest reporting 3GB in use, Real/RSS shows ~6GB.

I would raise a support case, but it seems my entitlement doesn't allow me to.

Has anyone ever had official confirmation from VMware support about what is going on?

[ColoradoMarmot]

I just checked and see this on my linux VM's too - 4GB configured, 7 and change in activity monitor.  My windows VM shows 32GB in activity monitor, but only has 16 configured.  Real memory is about 1/2 that for the linux VM's but still shows 30 GB for the windows one.

I suspect this is an activity monitor artifact on the vmware-vmx process, because if I add up the VM's in current use it would be 53GB (real memory is ~45GB) just for them, but the top line 'in use' number for the system is only 44.

Honestly, on apple silicon, unless memory pressure is turning yellow, I don't pay much attention to memory usage anymore.

[Technogeezer]

Other thoughts...

If you have disk caching turned on fin the VM's settings, that memory has to come from somewhere. And don't forget the "shared graphics memory" associated with the VMware SVGA adapter that I believe gets shared with the mksSandbox process. 

I've always found Activity Monitor's display/categorization of memory utilization somewhat difficult to interpret. 

[jlaundry]

I should've mentioned - I've tried numerous settings (each time going one-by-one, shutting down the VM, change the setting, start back up...) and apart from setting Compatibility Version to 19, none of these have had any effect:

• Turning Accelerate 3D Graphics on and off
• Changing the number of CPU cores
• Changing the HDD bus type
• Removing Camera, Sound Card
• Rebuilding with different Encryption options (All files vs only TPM files)
• Turning off Drag & Drop / Copy Paste
• Changing HDD buffering Enabled/Disabled/Automatic

I agree Activity Monitor's default Memory column is kinda meaningless, but the Real size isn't, and when you're trying to squeeze VMs alongside Teams, Edge, and all the other corporate noise that seems to have an endless appetite for memory, every bit matters...

[Technogeezer]

Are you just observing memory utilization, or are you observing excessive paging/swapping activity? Is memory pressure in Activity Monitor peaking into the red zone, and does "top" indicate excessive page ins/outs? Both of which would be accompanied by performance degradations on the Mac due to that excessive paging.

You're obviously using Fusion for commercial purposes.  You do have the option of purchasing per-incident support from the VMware store which would allow you to open a support request/ticket.