I have 4x AMD Opteron 6274 CPUs in an HP DL585 G7 server. Windows Server 2016 only shows these CPUs as having 12MB ea. of L3 cache, although every source on the internet says they should have 16MB (2x8MB) ea. of L3 cache.

When the server boots, it states that the CPUs have the expected 16MB of L3 cache.

Windows Server 2016 correctly reports their 16MB (8x2MB) of L2 cache.

CPU-z thinks that each CPU only has 6MB of L3 cache (or perhaps this is a bug in CPU-z, because at least it should report 2x6MB of L3 cache).

I have not disabled any cores in the server's BIOS, and have tried with turbo'ing enabled and disabled.

Any idea how I can get the full 16MB of L3 cache recognized? I'm using an application that depends heavily on cache. Thanks for your time.

  • 1
    You won't be able to change what Windows detects for obvious reasons(Windows is closed source). If there is a bug with how Windows detects the amount of L2/L3 memory then there isn't much you can do.
    – Ramhound
    Nov 8, 2017 at 21:47
  • OK, so it looks like many Opterons have a feature called "HT Assist" which increases the speed of communication between nodes. My particular task would benefit more from freed-up cache than increased HyperTransport speed. So this is not a Windows issue, and I need to figure out how to disable HT Assist on the HP DL585 G7. A Google search reveals others asking but no instruction in how to do it...
    – C.P.
    Dec 22, 2017 at 17:21
  • I am too facing the same issue on Windows 10 Pro. CPU-Z shows only 6MB for some reason. Could you please point me to where in Windows you can see amount of L2 / L3 Cache? Thanks.
    – AlexVPerl
    Aug 15, 2018 at 18:45


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