How many vCPU Sockets Do We Really Need

[Shahnawaz26]

For example, Windows 2008 standard is limited to 4 physical CPUs, and it will not utilize any additional vCPUs...

Says Frank Denneman in his Blog:  vCPU configuration. Performance impact between virtual sockets and virtual cores? - frankdenneman.nl

How many Physical CPUs ( Virtual Sockets ) does RHEL 5,6.X utilizes.

[rcporto]

Note, Windows Server 2008 Standard is limited to 4 (four) physical cpu (or sockets) BUT it supports 32 logical processors (in 32bit version) or 64 logical processors (in 64bits version)... then when cofiguring a Windows Server 2008 Standard, if you need more than 4 (four) logical processors, rememmber to increase the "number of  core per sockets" in virtual machine configuration.

About RHEL, take a look here for some limits: Red Hat Enterprise Linux technology capabilities and limits - Red Hat Customer Portal