When the OVA or AA is called form a Lync phone, the UM server CPU is over 90% and the playback is garbled.

We have another dialplan that is through a traditional PBX\SIP Gateway and this does not occur.

The UM server is on a Hyper-V machine.

Ideas as to why the Lync-UM is having this issue?

The umworkerprocess.exe is what is pegging the CPU.

Anyone have any suggestions?

Not sure what version of Exchange or Lync you have running, but whether it is a Lync connection into UM or a non-Lync connection into the same UM server, the experience should be the same.

What are the specs of your UM server?  How many UM Dial Plans and UM IP Gateways do you have associated with it?

UM server:

Host is Windows Server 2012 Standard

Hyper-V Guest with Windows 2008 R2

Memory allocated= 10GB Normal Priority

CPUs Allocated= 12 Normal Priority

Virtual LAN switch usage of the Hyper-V= We have tried with dedicating a team four adapters to VM.  Currently though we share 11 1G Nics  with 3 other VMs (MB, CAS, DC)

Exchange 2010 Sp3

2 dial plans- one SIP and one tel based

2 IP gateways (one Dialogic DMG1008 and then the Lync 1:1

AutoAttendants total= 3 for Lync and 2 for Basic

Lync Server

Host is Windows 2012 Standard

Hyper-V Guest with Windows 2012 Standard

Memory allocated= 8GB

CPUs Allocated= 16

Virtual LAN switch usage of the Hyper-V= 3 including 1 Lync Standard, 1 Lync Edge, and 1 Lync Monitoring Server

Lync 2013 Standard with latest CU

Is your VM running only the UM role of Exchange?

Assuming it is, you've allocated 10GB of RAM to it and 10 virtual processors to it?

When you say the playback is garbled, do you mean the system prompts heard are garbled or voicemail recordings being listened to are garbled?

During the time it is garbled, how many calls is the UM server actively handling?  Is voicemail preview enabled?