Weird RAM behaviour

Discussion in 'Parallels Desktop for M Series Mac' started by ErikK6, Jun 30, 2021.

  1. ErikK6

    ErikK6 Bit Poster

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    2
    Hey all

    My Windows 11 ARM VM (I believe it was the same with windows 10) is incredibly slow and unresponsive when using 4 or more GB of ram. It looks like the culprit is some kind of absurd ram usage. With the VM set to 4 or 8 gb of ram, ram usage is pegged around 98%+. It's unclear where this usage comes from as neither task manager nor resource monitor show numbers that add up to this usage.
    Weirdly enough, setting the max VM ram to a mere 2gb reduces ram usage to around 60-70% (a very normal value for idle usage on a 2gb VM) and performance is significantly improved.

    Does anyone else experience this?
     
  2. ErikK6

    ErikK6 Bit Poster

    Messages:
    2
    Behaviour remains the same even with 18gb of ram allocated to the vm (10gb more than I have in my machine)
    Activity monitor on the Mac also somehow reports the VM using 30GB of ram, although little of that seems to actually exist as swap and physical memory used only amount to around 9gb.
    Weird
    upload_2021-6-30_9-22-8.png
    upload_2021-6-30_9-20-6.png
     
  3. HenrikW4

    HenrikW4 Bit Poster

    Messages:
    3
    Yep. I have had the exact same experience. Windows was maxing our RAM when I allocated 4GB or more with really awful performance as a result. With 2GB everything went smooth and performance increased really dramatically. Thought I was going mad.

    Henrik
     
  4. DmitryL4

    DmitryL4 Bit Poster

    Messages:
    2
    Is it enough to windows to use only 2gb? I have the same issue, i'm setting 8gb of ram to windows all the time i see the same picture in VM task manager (98-99% of memory usage when running just os without any software) and memory pressure in macOS going to be yellow or some times red
     
  5. HenrikW4

    HenrikW4 Bit Poster

    Messages:
    3
    It defies all logic to me, and I have no idea why it works as it does. I would also hav thought that 2GB was way to little memory, but its with 2GB i get the best performance. Perhaps someone at Parallels can explain why
     
  6. madscene

    madscene Bit Poster

    Messages:
    6
    Same here. Posted in other threads as well. This has always been a thing with Parallels, over-allocating resources could result in performance issues, but I never saw anything this bad with the pegged resources on both sides.
     

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