Recommendations for VM


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Hi!

 

I’m building a new rig for an Unraid server.

 

- AMD Ryzen 3950x

- Gigabyte Aorus X570 extreme

- G Skill Neo Z 64 gb C16 ram memory

- Gigabyte Aorus RTX2080 ti xtreme

 

My question is: when I launch a Windows based VM to play 4K games, how many cores and memory should I assign to it? Considering that, mostly, Nobody else will be using the server while the VM is running (except, maybe, Deluge).

 

thank you!

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8 hours ago, Dreyfus Fabrini said:

Hi!

 

I’m building a new rig for an Unraid server.

 

- AMD Ryzen 3950x

- Gigabyte Aorus X570 extreme

- G Skill Neo Z 64 gb C16 ram memory

- Gigabyte Aorus RTX2080 ti xtreme

 

My question is: when I launch a Windows based VM to play 4K games, how many cores and memory should I assign to it? Considering that, mostly, Nobody else will be using the server while the VM is running (except, maybe, Deluge).

 

thank you!

Exactly 8 cores, and should be the last 8 physical cores (+ their hyper-threading sisters). 

  • The 3950X has 2 CCD's linked together with Infinity Fabric. You don't want to jump CCD when processing things as cache needs to be copied to the other CCD, introducing latency. The IO die design only mitigates cross-CCD latency but cannot eliminate it.
  • The 1st CCD (first 8 physical cores + HT sisters) contains core 0, which should generally be left free for Unraid to do Unraid things - so the 1st CCD can't be fully isolated. The 2nd CCD, in contrast, can be fully isolated to the VM in syslinux for the lowest possible latency.
  • 8 cores are more than enough for all current triple-A titles.
    • For games that don't need that many cores, 4 cores (i.e. same CCX) are probably even better for more consistent performance. But that's overthinking things in a sense.

RAM is less important. 16GB is sufficient for most games. 32GB is an overkill.

In fact, your rig, with the usage you are reporting, is an overkill. :)

Edited by testdasi
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  • 2 weeks later...
29 minutes ago, Dreyfus Fabrini said:

Just one question: in your opinion, would you think that it would be better to boot the computer with Windows 10, so that I can get the full resources for Windows, or should I just start the Windows through VM?

Let's flip the question over: is there anything in Unraid that you can't do in Windows barebone?

 

If there is, you really don't have a choice but to use Windows as a VM.

If there isn't then you should stick to Windows barebone for simplicity and best performance.

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Well then you need to consider if you actually need the storage feature of Unraid.

  • If you do then you can dual-boot and boot into whichever one that you need at that time. Take care not to format your xfs-formatted drives because Windows like to nag about that.
  • If you don't then you might as well boot into Windows only.

 

One thing that you may have not considered: do you want to isolate your Windows machine (VM) from your storage e.g. in case of cryptovirus infestation?

That was actually one of the main reasons I run a Windows VM under Unraid (instead of, for example, running a Linux VM from within Windows). Let's say I'm somehow infected with a crypto-virus, I can recover extremely quickly by simply killing off my infected VM and recopy my data from my backup (saved on the array) to my new VM (NVMe drives).

It would take extreme hacking skill for the virus to spread from my Windows VM onto my Unraid array backup (it's not even exposed to the network).

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28 minutes ago, Sleepyme said:

Do we need to worry about the ccd thing for a 3900x?

Yes. The 3900X and 3950X both have 2 CCDs.

In fact, you can pretty much consider the 3900X / 3950X to be the (improved) successors of the Threadripper 2920X / 2950X.

The key improvement is having an IO die so you don't have to worry about NUMA node optimisation.

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51 minutes ago, testdasi said:

Yes. The 3900X and 3950X both have 2 CCDs.

In fact, you can pretty much consider the 3900X / 3950X to be the (improved) successors of the Threadripper 2920X / 2950X.

The key improvement is having an IO die so you don't have to worry about NUMA node optimisation.

Which cores should i be assigning to my vm? Similar to the 3950x (last 6 cores)? 

Edited by Sleepyme
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