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Windows 7: Changed MTU size, reverted back to default, noticable lag now

07 Jan 2013   #1

MS Windows 7 Home Premium 64-bit SP1
Changed MTU size, reverted back to default, noticable lag now

Hi, well first of all the reason I changed it was because I tried to optimize (my mistake) by reducing it. My router is set to 1365 MTU manually after a support tech from Linksys asked me to change it for a previous problem. I used the "netsh interface ipv4 set subinterface "Wireless Network connection" mtu=nnnn store=persistent" command to change it around to find what MTU Windows uses automatically. It was set at 1500 (for both LAN and WLAN). I set the WLAN to 1365 to see how it would perform, didn't see a noticable change I believe so I switched back. Now I see a slight lag when loading sites. I also compared the time against another pc that I did not tamper with (which by default was set to 1500) and that one worked normally.

I fear I may have overridden Windows defaults for handling MTU since after manually setting it to 1500 (was originally 1500 when it was untouched) it lags a little. For the time being I set it to 1365 to get the performance that I normally got with default settings.

My question is if it's possible to get the original performance back with the MTU set back to what it was originally (1500)?

Also I learned my lesson and won't be trying to change settings without first making sure they are completely reversible. Also I'd like to do this without using System Restore.

Thanks in advance.

My System SpecsSystem Spec
09 Jan 2013   #2

Windows 7 Pro x64 Windows 10 Pro x64

What browser do you use.
My System SpecsSystem Spec
09 Jan 2013   #3

MS Windows 7 Home Premium 64-bit SP1

Firefox 18. Also where in the adapter settings did you say I could find the Mbps, I didn't know that was possible from there. From online speed tests I get ~15 Mbps and down and 2 Mbps up.
My System SpecsSystem Spec


 Changed MTU size, reverted back to default, noticable lag now

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