# How can i force the adapter to not auto negotiate to 1gbs.  I need to force it to 25 gbps on Windows Server 2019.

**URL:** <https://forums.developer.nvidia.com/t/how-can-i-force-the-adapter-to-not-auto-negotiate-to-1gbs-i-need-to-force-it-to-25-gbps-on-windows-server-2019/206736>\
**Category:** Adapters and Cables\
**Tags:** mst\
**Created:** [August 19, 2019, 1:22am UTC](https://forums.developer.nvidia.com/t/how-can-i-force-the-adapter-to-not-auto-negotiate-to-1gbs-i-need-to-force-it-to-25-gbps-on-windows-server-2019/206736 "2019-08-19T01:22:53Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![dbomgardner](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@dbomgardner](https://forums.developer.nvidia.com/u/dbomgardner)\
**Post date:** [August 19, 2019, 1:22am UTC](https://forums.developer.nvidia.com/t/how-can-i-force-the-adapter-to-not-auto-negotiate-to-1gbs-i-need-to-force-it-to-25-gbps-on-windows-server-2019/206736/1 "2019-08-19T01:22:53Z")

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Apparently there is a command in linux that does this: ethtool -s speed 25000 autoneg off

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**Author:** ![samerka](https://sea2.discourse-cdn.com/nvidia/user_avatar/forums.developer.nvidia.com/samerka/32/367020_2.png) [@samerka](https://forums.developer.nvidia.com/u/samerka)\
**Post date:** [August 19, 2019, 5:26am UTC](https://forums.developer.nvidia.com/t/how-can-i-force-the-adapter-to-not-auto-negotiate-to-1gbs-i-need-to-force-it-to-25-gbps-on-windows-server-2019/206736/2 "2019-08-19T05:26:32Z")

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Hi Daniel ,

You can use the mlxlink tool part of the MFT (Mellanox firmware tools)

[https://community.mellanox.com/s/article/mlxlink](https://community.mellanox.com/s/article/mlxlink)

#mst start

# mst status to get the device id

i.e

/dev/mst/mt4115\_pciconf0

Set the speed to 1G

# mlxlink -d /dev/mst/mt4115\_pciconf0 -s 1G

Toggle the link

"mlxlink -d /dev/mst/mt4115\_pciconf0 -a TG

To verify changes run :

mlxlink -d /dev/mst/mt4115\_pciconf0 -emc

Thanks,

Samer