I have 2 VMs running on a ESXI 6.0 Host with W2012R2 and VMXNET3. With iperf I get around 982Mbits/sec. Also tried to a outside VM (HyperV) running on another server and I get 300Mbits/sec. Download from that same outside VM to my laptop directly connected to the Procurve 2824 I get max link speed copying a file trough SMB.

Already set all Jumbo Frames (9000) on both VMs and also on the configuration of the vSwitch. What else can be wrong?

NIC Teaming is based on virtual port ID with 2 NICs.

Thank you


Does that outside VM have the legacy adapter or the "network adapter" attached? You need integration tools installed for the one called network adapter and not for the legacy adapter. The legacy adapter is slow.

It is the EXACT same problem with VMXNET3 vs the E1000. We had a client that had nothing but problems in their environment with connectivity issues with the RDS Farm. Changed all VMs to VMXNET 3. Flawless. Same with Hyper-V. We've had throughput issues with the Legacy Adapter.

  • If you're trying to get the 10Gbps speed of the VMXNET3, that only works going between VMs on the same host if your Host box's physical connections are only gigabit. It will fail over the connection to another NIC if one physical host NIC connection goes down. But the only way to get the full 10Gbps (though not clear in the question exactly) is to have a 10Gbps daughter card in the host. – PCFixerGuy Aug 16 '16 at 22:57
  • So if I got it I can only achieve 10Gbps if my host NIC is 10Gb also? Even if it's inside VMs on that same physical host? If my host card is 1Gbit I will only get 1Gbit beetween VMs? – rgomez Aug 16 '16 at 23:55
  • If you have more than one vSwitch for a host where you have them on separate ethernet ports, you'll be limited to 1 Gbps between vSwitches. If you make it so everything is on one vSwitch and just use the NICs in failover fashion, they will communicate with each other directly through the vSwitch at the full 10Gbps. What you DON'T want to do is tie a VM directly to a single physical NIC. It would still create a vSwitch as it converts the interface to virtual, will show that it's a 10Gbps connection, but will only be at a rate of 1Gbps max. – PCFixerGuy Aug 19 '16 at 14:22
  • Can also get all your hosts NICs on 10Gbps for not a huge ton of money. A lot.. but the speed.... omg the speed... amzn.com/B00B46AEE6 - 8-port 10Gbps Switch & amzn.com/B015HDT6AY - Dual 10Gbps NIC compatible with VMware – PCFixerGuy Aug 19 '16 at 14:25

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