Windows 10, 10gbe connection slow transfer, DefaultSendWindow / tcp

Hey

I did a bit of research on this matter and I'm pretty sure I have narrowed it down to windows DefaultSendWindow being set too low for modern networks.

Where can I edit this setting in windows to force a different tcp buffer length size.

I found this on internet TCP Window size problems


and this in that post

You can do that by editing the registry key:HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\AFD\Parameters\DefaultSendWindow

But this is empty on my end and I don't know what values I should put in to configure that.

A more 10gbe related topic on this I have posted on this forum, in case any1 is interested.
10gb SFP + network setup - slow windows TCP Transfer - Spiceworks

From my tests over there you can see that the windows is the issue of slow transfer speeds and not hardware/zfs/freenas.

Regards
Dariusz

Whats your mtu set to?

Hey all

Thanks for help & ideas!


@bro67 I have 2 ethernet connections, 1 for internet, 1 for private offline network. the internet one is 1GB the Private one is 10GB. Maybe windows takes the test result from the 1GB internet network and applies to all interfaces, not sure. I don't think its the CPU, as you can see on the other forum where I posted Jperf results. Also how can it be cpu if I can upload to NAS at speed of 300MB but only download at 100MB ? Does not make sense. I was able to download at 700MB+ on old workstation and this one is even faster.

@Samuria - I just run tests, Used this for guide : Changing the MTU size in Windows Vista, 7 or 8 (mtu, speed, windows, Windows 7, Windows 8, Windows Vista)
, I tried 3000 and 9000. No change :- (

@TairikuOkami - I will check it out today. Thanks!

I also went over this post A word about AutoTuningLevel Hybrid Networking | Cloud and OnPrem
Seems to be latest -most up to date information.

I'm fairly sure its down tow indows. Seeing how often MS changers/tweaks TCP managment system. Old windows which was installed like 3 years ago worked quite fast out of the box with 10GB connection. The new windows does not the only conclusion I can come with is that there is a setting buried somewhere that is messing stuff up.

Thanks all for help, will keep it posted if I figure it out.

Hey
@bro67
I'm not sure where the confusion is coming. I'm sorry if I'm unclear somehow. to put it simply TLR The hardware is not the problem, old windows yielded 800MB/DL and 300MB/UP. New windows yields 100MB/DL and 300MB/UL. There is NO HARDWARE LIMITATION HERE. I simply installed windows on new workstation - now workstation is not your average pc here. Its 2990WX based rig running M.2 as only drivers. There is also no transfer happening between the 1Gb network and 10Gb one. The 1Gb is intended for internet access and 10Gb for internal nas/data transfer. The Jperf tests do show that if I change the buffer size from default to 16/32mb I'm getting fast transfers. So it the issue must be OS.

(I think its 1Gb not 1GB right? Still getting a hang of the gbGBGb names).

Also the more I look in to it the more I see people having the same problems on FreeNAS forum. Where they have 300MB limit of data transfer. Problem is that there is nothing that can be changed other than tunables. So not sure what else to bite there. So I'm fairly sure its the windows. As my old Windows worked better than the current one.

Dariusz said:

Hey
@bro67
I'm not sure where the confusion is coming. I'm sorry if I'm unclear somehow. to put it simply TLR The hardware is not the problem, old windows yielded 800MB/DL and 300MB/UP. New windows yields 100MB/DL and 300MB/UL. There is NO HARDWARE LIMITATION HERE. I simply installed windows on new workstation - now workstation is not your average pc here. Its 2990WX based rig running M.2 as only drivers. There is also no transfer happening between the 1Gb network and 10Gb one. The 1Gb is intended for internet access and 10Gb for internal nas/data transfer. The Jperf tests do show that if I change the buffer size from default to 16/32mb I'm getting fast transfers. So it the issue must be OS.

(I think its 1Gb not 1GB right? Still getting a hang of the gbGBGb names).

Also the more I look in to it the more I see people having the same problems on FreeNAS forum. Where they have 300MB limit of data transfer. Problem is that there is nothing that can be changed other than tunables. So not sure what else to bite there. So I'm fairly sure its the windows. As my old Windows worked better than the current one.

@Dariusz I know this is an older thread but was there ever a resolution to this? I am having a similar issue and seem to have exhausted the knowledgebase of the internet.

Anim8me2 said:

@Dariusz I know this is an older thread but was there ever a resolution to this? I am having a similar issue and seem to have exhausted the knowledgebase of the internet.

Yeh I managed to get it run fast at the end. But then did format 2 days ago and I'm back to being slow again! WRRRRRrrrr!!!!

Right now I'm 500-750 upload and 40-50 download, ehhh as if for some reason incoming packets to windows are somehow damaged or something ;/

Googling again on how to fix that.

Looks like I had some luck here > 10gb SFP + network setup - slow windows TCP Transfer - Spiceworks