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Jeff_Riechers's avatar
Jeff_Riechers
Copper Contributor
Mar 04, 2024

VMXnet3 Server 2025 performance issues

Had an odd one crop up today.  I updated my Server 2025 template to the 26063.1 release and then sysprepped it.  Converted it back to a new VM and network performance was .25 Mbps down.  Both on my l...
networking
alexeybes's avatar
alexeybes
Copper Contributor
Dec 23, 2024

I had same issues. After I disabled all kinds of "offloads" and "interruptions" options VMXnet3 works fine.

Jeff_Riechers's avatar
Jeff_Riechers
Copper Contributor
Dec 24, 2024

I have moved back to E1000 at this point so I can use NVMe memory tiering.  Some people have started seeing issues with Windows 11 24H2 as well.  Do you have a breakdown of the mods you did so I can test them in my lab?

  • alexeybes's avatar
    alexeybes
    Copper Contributor
    Dec 29, 2024

    Control Panel - Network and Sharing Center - Change adapter settings
    Right Click on vmxnet3 Ethernet Adapter - Properties - Configure... - Advanced

    Interrupt Coalescing Sheme Mode - Disabled
    Interrupt Moderation - Disabled
    IPv4 Checksum Offload - Disabled
    IPv4 TSO Offload - Disabled
    Large Send Offload V2 (IPv4) - Disabled
    Large Send Offload V2 (IPv6) - Disabled
    Offload IP Option - Disabled
    Offload tagged traffic  - Disabled
    Offload TCP Option - Disabled
    Priority / VLAN tag - Priority & VLAN Disabled
    Receive Side Scaling - Disabled
    Recv Segment Coalescing (IPv4) - Disabled
    Recv Segment Coalescing (IPv6) - Disabled
    Speed & Duplex - 10 Gbps Full Duplex
    TCP Checksum Offload (IPv4) - Disabled
    TCP Checksum Offload (IPv6) - Disabled
    UDP Checksum Offload (IPv4) - Disabled
    UDP Checksum Offload (IPv6) - Disabled

    I'm not sure which one helped.
    Didn't have time to check one-by-one.

    • Karl-WE's avatar
      Karl-WE
      MVP
      Dec 31, 2024

      You could enable RSS (receive side scaling) and check if this makes it better. With 4+ vCPUs it should.

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