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Help choosing CPU


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Dear unRAID users,


After a couple of days of research about different hardware and software raid setups I came across unraid 6.

It got me very excited and now I'm thinking of using unraid as the OS for my home server.


However with the virtualisation that unraid offers, I'm now thinking about hosting at least one, maybe a few VMs. One of these will be a Windows 10 VM for gaming.

Here is where my question comes around :


What kind of CPU benchmark do I need to run a "high" end gaming rig as VM, next to unraid and plex media server which needs to be able to handle 3 1080p streams simultaneously.

For the transcoding part I know I need around 2000 passmark per stream.


So can I just pick a CPU, get the passmark - 6000 and compare that to most competitive CPUs in gaming rigs?

I'm looking to run one 970, possibly a 980TI in the VM, and don't want the CPU to bottleneck.


I would love it if some people could shine some light on the subject of running 1 gaming (60+ fps 1080p) VM next to 3 1080p plex trancoded streams.


Thanks a ton :)

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If you buy a new system you won't likely risk running into a CPU bottleneck unless you chose a really low end CPU. As long as you start off with at least a quad core i5 you will be fine. You want at least a quad core if you want to do virtualization, the more cores the better as you want to at least dedicate two cores per VM, depending on what you are doing. You also have to remember to leave cores and memory for UnRaid to use as well. You might also want to consider getting an SSD or two for your VM's. I run a windows 10 VM for gaming on my second UnRaid server and have a 256 SSD dedicated for that VM, I pass an Nvidia GTX 960 through to it and have dedicated two cpu cores and 4GB of RAM (system has 32GB of RAM and a quad core i7 cpu) and the VM runs like stink.

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Regarding storage; I'll be running 2 SSDs in the cache pool, but thinking dedicating 1 to the VM like you mentioned.


Also, I was considering a Xeon E5 2620, because I read that more cores would be beneficial, but I'm scared it will cut into my game performance, since it doesn't have that strong of a single core performance.


But a chip like the I7-5820 would be enough considering my needs?


Lastly, when assigning cores to the VM, can I assign 4 of the 6 cores to the windows VM and leave 2 for unraid to transcode / memory manage etc?

And when the transcoding of the streams hits 100% CPU on those 2 cores, will it pool more power from the other 4 cores reserved for windows, or does unraid just max out the 2 cores and leave the rest of the cpu alone?


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More cores are beneficial but it really depends on what you are going to be doing, if you are going to running a bunch of VM's simultaneously, than sure, more cores is better as you'll need them. If you are only going to run one VM at a time, then you don't need so many cores. A quad core i7 should be more than enough for your needs. Also, you'll seldom find a situation where you will need to assign more than two cores to a VM. In virtualization there is a thing called 'over provisioning' its a trap many people fall into where they assign too many resources to a VM and this ultimately backfires and hurts the performance of the vm. If you assign too many cores and too much ram, the VM won't use it all and it will be wasted. My advice is start out small and add more resources if needed. So start off building your Windows 10 VM with two cores and 4GB of RAM, if you find that task manager is showing your two cores maxed out a lot of the time, than sure, add another core and see id that helps, likewise if you find that 4GB of memory is not enough and your  memory usage is maxed out a lot of the time, add another 2GB of RAM and see if that helps. It really boils down to how you are using your VM for and what the workload is, is it more cpu intensive, memory intensive etc.

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Thank you so much for the excellent reply, really appreciate it.


Especially regarding over provisioning. When a VM is so easily scalable / manageable ,  why shouldn't you make a few iterations to find out the true resources, yet I never thought of it.


I might scale down to a I7 6700k than instead of the beast that is 5820k, I now at least have some more information to work with, cheers!

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  • 2 weeks later...

It means that within the UnRaid OS, you can install a 'virtual' instance of Windows 10, with a dedicated video card, connect a monitor and a keyboard and mouse to the UnRaid server (passthrough the video and keyboard and mouse) to the virtual machine.


I have a monitor on my desk and with a keyboard and mouse that are all connected to my UnRaid Server.


From my UnRaid server, if I go to the VM tab I see this the details of the virtual machine


If I click on the actual VM icon, I get more options.


When I start up the virtual machine, my monitor comes to life and boots windows, I can then login and play games on this windows 10 virtual machine that is actually running on my UnRaid server.





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Cool, thanks for the explanation

So I assume if I just want to use that Virtual windows machine for just emails, web browsing, youtube, facebook, etc.....there is no need for a powerful video card, right?

Also, it means the server needs to be close to were you have your keyboard, mouse and monitor....So server in the basement or a closet is not ideal, right?

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It depends if you want to actually do video passthrough or not, if you do, then yes the keyboard/mouse and monitor need to be physically connected to the server and close you. If you don't want to do video passthrough, you can still do the VM but connect to it via VNC which is a remote utility available to the VM. I should mention if you want to do video passthrough you need a motherboard and CPU that support VT-D as it is necessary to do the passthrough.

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Why would I want (or not want) to do video pass-through?

I'm not sure to understand the 2nd option, with the VNC....In that case, where is attached the keyboard, mouse and monitor?


I was looking at the FX-8320E (because it's cheap), but I believe they don't support VT-d, right?

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They way VNC works is like this, you log into your UnRaid server, through the web browser, and as in my screen shots you start the VM, and it launches another a VNC window with the vm booting in it, you use your same keyboard and mouse to use the VM. But I suppose if you need a computer in the first place to connect to your UnRaid server so why have a vm then....Video passthrough gives you the full power of the video card, so for people like me who want to game, its necessary. If all you are doing is web browsing and email, you don't need a very powerful video card at all.

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Right now, my server (v5.0.5 - very basic with a Sempron LE-1100) is in a closet. My wife's desktop is close to it actually....If I were to run cables from the server to the her desk, it would be 10 ft max

So in that case, I could upgrade my server and virtualize a  Windows 10 machine for her.....


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