When comparing two different VM series in Azure, I see that one has Cores and the other one vCPUs. Keeping aside the number of Cores/CPUs, Memory and Processor Type (Intel Xeon E/Platinum etc), what is the advantage of one over the other? I understand that CPU can have multiple cores, but in Azure what is the difference between 4 vCPUs and 4 vCores?
G Series with Core
D Series with vCPU
This is down to whether you get a real core or virtual core.
Older VM SKUs, and some specialised SKU's like H series have a 1 to 1 mapping between physical cores in the host machine and cores in the VM, so you are getting a real core dedicated to your VM, no hyperthreading.
Most recent SKU's, v3 and newer, are using hyperthreading and so the core allocated to your VM does not map 1 to 1 to a physical core in the host machine.
I'm not super familiar with Azure terminology but I suspect it's the same as in AWS: "Core" sounds like a real physical CPU core while "vCPU" typically refers to 1 thread in hyperthreading-enabled .
See Optimizing CPU Options: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/instance-optimize-cpu.html
in all cases vCPUs is number of threads per core which defaults to 2 and only 1 or 2 are valid values
