Comments on: What is Virtual Processor or vCPU?

By: andrew

andrew — Wed, 23 Nov 2022 03:49:55 +0000

why x8 ? CPU E5-2650 has 16 threads

By: Rahul V

Rahul V — Wed, 29 Apr 2020 13:53:36 +0000

In reply to Srini.

Hi Srini,

Our calculation is for fair usage. This allows you to allocate more virtual CPU based on requirements. But you cannot use more than total number CPU cores which are available on the physical host. If your physical server has 28 cores, you cannot use more than 28 cores and some virtualization may not even allow you to set higher number of CPU cores than total available physical cores. Whenever you are going to host many VMs on a physical server, you have to monitor the performance of the host server. This will ensure that you are not running out of CPU processing power.

Thanks!

By: Srini

Srini — Thu, 23 Apr 2020 15:24:14 +0000

if I have Xeon platinum processor with 28 cores and capable of hyperthreading, based on your calcs it should then support ( 28 x 2 x 8 = 448 vCPU’s)
Also, VM ware recommends A virtual machine cannot have more virtual CPUs than the number of logical cores on the host. that being said the number of VM’s possible with the above processor is 448/56= 8 VM’s max. Am I right ?
If the above calcs are correct and If I have an application that needs 32cores to run on a physical server, and If I want to virtualize it on the above server with Xeon plantinum 28 core processor, should I be looking at 32 vCPU’s per VM ?
Appreciate your thoughts on this.

By: Rahul V

Rahul V — Sat, 18 Jan 2020 06:19:55 +0000

In reply to Stephen.

The 16 vcpus assigned with a VPS are shared among other VPS hosted on the same server. However, in a bare metal server, if there are 4 cores, they are dedicated to your requirements. So, VPS are mostly cheaper than dedicated servers.

By: Stephen

Stephen — Fri, 17 Jan 2020 14:54:37 +0000

Btw i have a general question if you can help with it. i seen some small dedicated server with 4 core is costly than a VPS with 16 vcpus / core .. can you please advise on it ?

By: Jason-Pat

Jason-Pat — Tue, 23 Jan 2018 08:26:23 +0000

In reply to Peter.

Hello Peter,
Thanks for the feedback. We have updated the CPU cores and the table on the blog. Please note that we are considering 8vCPU/cores and not 16vCPU/core as recommended by Microsoft here.

By: Peter

Peter — Fri, 19 Jan 2018 01:27:47 +0000

The Intel Xeon CPU E5-2650 v2 has only 8 cores. You mentioned 16 cores! It has 16 threads as each core can support 2 threads. So 16 vCPU shares 1 core of 2.6Ghz. So each vCPU only has 0.1625 Ghz! That’s so little. This is why VPS with 1 or 2 vCPUs are very slow. The other thing to notice is that the real speed of each vCPU depends on the model of the real CPU. The newer and more expensive ones are faster so teh vCPUs are faster too. But then nothing stops hosting companies to dilute that power by adding more vCPUs per physical core. So there does not seem to be any standard at all. There is no way for users to know how fast each vCPU is unless the hosting company publish info on vCPU they have set up in term of clock speed in Ghz.