much of a gain by assigning more than 1 vCPU per VM?

ESXi:       5.1.0, 1483097

Model:     Intel i7-3930k 3.20GHz
Processor Sockets:                 1
Processor Cores per Socket:    6
Logical Processors:                 12
Hyperthreading:                        Enabled
Memory:                                  32GB

i'm trying to make sense of this doc, www.vmware.com/pdf/Perf_Best_Practices_vSphere5.5.pdf , but this will take a few more reads for me and my experience.

i have 4 linux VM's and one Win2008 server VM. none of the VMs run any intensive type DB stuff, basically desktop stuff and one is a syslog server for other items on my home net.

i have one of the linux VM's assigned 3 vCPU and all others 1 vCPU.

my question is, do i gain much here by assigning >1 vCPUs for any of these VMs ? or is 1 vCPU sufficient?