Hardware Reserved RAM inside a Virtual Machine?

Windows Server 2008 System Reserved RAM

At a client site I came across something that I hadn’t seen before whereby Server 2008 R2 would reserve almost half of the available RAM for system devices and call it Hardware Reserved RAM.
Out of 46 Gig available, 20 was assigned to system devices of which 10 GB was assigned to a block of PCI-e ports.

Windows Server 2008 System Reserved RAMHaving never come across this before I decided to dig around a bit deeper.

Opening up the Device Manager and changing the view to be Resources by connection, it was then possible to see the different memory blocks that were allocated.

From this screenshot we can see the PCI bus has about 10GB of RAM allocated.

Device Manager RAM usageExactly why it’s doing this or how to fix it is something I’ve yet to work out.

This article goes into detail about how to see what’s using your memory, but doesn’t explain why this would happen on a 64bit operating system. More research is required, I’ll post back any findings.

Author: Mike

Mike Streetz is a Citrix Consultant who works with everyone from small businesses to large enterprises to help their users get work done via Citrix Virtual Apps and Desktops. He has been working in the Citrix space for over 10 years. Mike knows that your users don’t want long logon times, don’t want long waits for files and don’t enjoy when “Citrix is slow”. His job is to help you get the most out of your Citrix environment. Mike has worked with clients to optimize user experience by using tools such as FSLogix alongside Citrix ADC with Global Server Load Balancing to point users to the fastest site to serve their needs. Mike is a Citrix Technology Advocate, CUGC Leader of the Los Angeles chapter, Citrix Certified Professional in Citrix Cloud, Virtual Apps and Desktops and Citrix ADC and holds the Azure Administrator Associate certification. He has previously spoken at the Ruxcon security conference in Australia.