Essential Guide

How to choose the right VMware type-2 hypervisor

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Q

Which CPU settings deliver optimal VMware Workstation 9 performance?

Newer processors pack more punch, but administrators still need to tailor CPU allocation for a smoother Workstation 9 experience.

Which processor settings in VMware Workstation 9 are better: two processors with four cores per processor or four...

processors with two cores per processor? The Workstation 9 system in question has an Intel Core i7-3820 processor running at 3.6 GHz, with four cores and eight threads.

When creating a virtual machine and choosing the processor settings, I can only make a VM whose total processor cores equal or are less than eight, otherwise I get this notification: "The virtual machine may perform poorly or fail to power on because the total number of processor cores exceeds the maximum supported value of 8."

Physical CPUs are always better than cores, and cores are better than hyper-threading. The benefit of having a physical CPU is its dedicated connection to memory. If two cores are available on one CPU, the cores share the memory connection, which decreases performance.

In hyper-threading, even more components are shared. A hyper-threaded CPU is like a virtual CPU core, but cache and other peripherals are shared, which means there is an even bigger performance hit.

In your configuration, the one physical CPU has four integrated cores with two hyper-threaded CPUs per core -- or an eight-CPU machine. Creating a virtual machine with more than eight CPUs means more than one virtual CPU has to run on one hyper-threaded CPU, leading to bad performance.

For best performance, make sure you never get beyond the total number of hyper-threaded CPUs on a machine.

This was last published in October 2013

Essential Guide

How to choose the right VMware type-2 hypervisor

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I think that the question is: given that you have a 4-core HT processor (i.e., the i7), is it better to tell workstation that you have 1 processor w/2 cores or 2 procs w/1 core (assuming that you want to run a 2 vCPU VM on the 4 core processor).
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You gotta be kidding me, who wrote this a 5 year old? You didn't even answer the question. Whats the best way to configure it? If I were to imply the answer by what you wrote I should put that I have 8 cpus and that cannot be right since there is only 1 cpu with 4 cores.... the real question being asked is should you put 4 CPUs and 8 cores? or just 1 CPU with 8 cores? Or 1 CPU with 4 cores (hyperthreading left out of the equation). Whoever got paid for this this article really shouldn't be writing this garbage! give the configuration, not the basic theory which anyone should already know, CPUs are better than cores are better than hyperthreading...no duh!
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I meant to say 4 CPUs and 2 cores, not 4 and 8...
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Here is a much better explanation that gives real answers:
“Giving it the real numbers, especially on an i7, shouldn't hurt you. It depends, also, on the type of processor usage you expect to have and the number of virtual machines running concurrently. If you are feeling like maxing out everything at the expense of even the host machine, you would want to go with 1 processor and 8 cores. On my i7 975 Bloomfield, I simply set it to 1 processor and 4 cores, but I have one VM running at a given time, usually.

If I were to know I was running, for instance, 4 VMs at the same time, as you apparently are, I may consider limiting each workstation to 1 processor, 1 core using division. However, even if you set all 4 VMs to use 1 processor and 4 cores, the resource allocation in Workstation would be capable of sorting it out for the most part.

Remember, that using extra processors has been designed for server motherboards that actually support more than one physical processor. You can get away with configuring your VM for multiple processors, for example 2 procs and 2 cores, but it may not be as efficient as just sticking to the basics. It is important that hypervisor has a real reflection of the conditions on the host computer to allocate to the virtual machines.”
http://windowsforum.com/threads/optimal-number-of-processors-for-a-virtual-machine-in-vmware-workstation.74100/#post-251510
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