This is page: http://msdn.microsoft.com/en-us/library/aa366778%28v=vs.85%29.aspx

I see: Windows Web Server 2008 R2 Limit on X64: 32 GB In my system display, I see: Only 16 GB are usable. Any ideas?

Thanks for your help

Only 16 GB are usable

Specs: PowerEdge 2970 - Quad Core AMD Opteron蒂 2372HE 2.1GHz 4x512K Cache 1Ghz HyperTrnsprt

  • 5
    That is odd indeed, what's your server make/model & exact memory loadout?
    – Chopper3
    Jun 27, 2011 at 12:15
  • Have you got any additional switches (e.g. /PAE, /3GB, etc.) for your OS booting entry in boot.ini file?
    – Sergey
    Jun 27, 2011 at 12:27
  • 2
    @Sergey: Server 2008 and up no longer use boot.ini. The closest analog would be the Boot Configuration Data store
    – jscott
    Jun 27, 2011 at 12:31
  • 4
    @Sergey & @JScott, and in addition to the whole boot.ini thing not existing for years, the /pae and /3GB switches have never worked on amd64 platforms.
    – Chris S
    Jun 27, 2011 at 12:40
  • 2
    Cucumber can I ask you to please calm down, read our FAQ and try to understand how this board works as right now you're making something of a fool of yourself. This is a Question and Answer site, not a forum or social network, if you want to make a comment then add it as a comment. I'm moving this to being a comment, as for your other 'answer', its just not.
    – Chopper3
    Jun 27, 2011 at 13:14

1 Answer 1


Run "perfmon /res" on your server. Check the memory tab. I'm betting that there's 8GB specified as hardware reserved. This could be because of actual hardware needs, but I think it's more likely that you're running a memory configuration that your motherboard doesn't support. Here's a Microsoft KB article that may shed some light on your situation:


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