Processor Recommendations

In Lync Server 2010 there was a support limitation of four vCPUs per virtual Lync server, even though eight cores were recommended for a physical Lync 2010 Server. This limitation stemmed from Windows Server 2008 R2 Hyper-V supporting only four vCPUs per guest machine (and therefore Microsoft tested for support only to this level). This was the primary reason for virtualized Lync Server 2010 being specified to support approximately half the number of users of a physical server.

With Windows Server 2012 this Hyper-V limitation is removed (Server 2013 Hyper-V guests can now support up to 64 virtual CPUs), and as such the 4 vCPU supportability limitation on Lync Server 2013 is also removed.

Lync Server 2013 Front End Servers, Backend SQL Servers, Standard Edition Servers, and Persistent Chat Servers are recommended to have six cores. Edge Servers, standalone Mediation Servers, and Directors can have four cores.

The high core count is because processing media requires many CPU cycles. Microsoft recommends dedicating logical cores to each virtual machine, and not overcommitting the cores assigned to Lync Server 2013 Servers. Where possible, use of Media Bypass will reduce the processing load on Front End servers with collocated Mediation Servers.