ESXI 6.5 - Intel gigabit ct slow performance

[Hyrules]

Hi everyone,

I'm having a small issue with my esxi 6.5 and an intel gigabit ct EXPI9301CTBLK which are supposed to be supported by esxi. I can't seem to achieve gigabit speed. Whatever I do I cannot seem to go faster than 70 mbit/s when trying a speed test. I have tried this in 2 Ubuntu VM and 1 Windows VM and they are all about the same speed. I have tried to update to 6.5U1 but that does not seem to fix the problem. I have also tried passthrough and the same problem exists can't seem to get faster than 70 mbits/s. If I switch my vm to the VM Network everything works fine. The nic are not on the same port group and virtual switch. The nic and exsi reports that the nic are at GB speeds. I want to dedicate nic to specific machines. Any help would be appreciated. Thanks.

[parmarr]

Hello,
    
     Please see if there is anything that you can use from the thread   https://communities.vmware.com/thread/563731

Hello,

Please see if there is anything that you can use from the thread https://communities.vmware.com/thread/563731

[Hyrules]

Thanks I will take a look at it.

[Hyrules]

Unfortunately that does not fixes the issue. I have also looked at this issue on the vmware KB but that also did not do it.

Low virtual network I/O performance with Intel 1Gbps NIC using igb driver (2018891) | VMware KB

For some reason there seem to be some kind of issue with the Intel drivers.

[Hyrules]

after some more investigation it seems that the nic is stuck at 100MBits full duplex even if it is detected at 1000 or manually set to 1000 full duplex.

[Hyrules]

more investigation done. Reinstalled vmware esxi 6.5and deleted datastore the issue still happen. I also tried xenserver and the issue is still occuring so there is something with the adapter. The odd this is that I have 2 of thoses in my server and they both have the same issue...

[Hyrules · Accepted solution]

finally after the latest investigations I was able to find out that my switch for some reasons was on a 100 mb link with the router. So the link with the switch was at 100 but when I tried to connect to the internet I was capping at 100.