Did you know that you can virtualize your TMG firewalls using Hyper-V? If not, you should! I have virtualized just about all of mine for years and I can tell you that it works great! It’s easy to do and the firewalls never die, especially if you run them on Windows Server 2012 R2. But there are a few tricks you need to understand, and one of those relates to memory requirements. In this article you’ll learn about those.
http://www.isaserver.org/articles-tutorials/configuration-general/hyper-v-virtual-memory-considerations-forefront-threat-management-gateway-tmg-2010.html
HTH,
Deb