RTL811E/Windows Poor performance

Frozennova · 22 Sep 2014 at 21:43

Trying to diagnose an issue that's causing slow speeds between my pc and my home server.

I have rule out hardware and narrowed this down to a windows specific issue, present on 7/8/8.1 with a mix of drivers from the newest to some older ones that are reported to be better.

both Debian and Linux Mint will both return 950M/bit speeds testing with iperf. About the best you are going to see with Gigabit due so a 5-10% overhead, while windows will not go above 750M/bit.

Link speed is negotiating correctly in Windows, I've tried connecting direct rather than through the switch they are currently connected to an I have tried from standard frame sizes right through to 9K MTU.

I also tried with a PCI Intel Pro Gigabit NIC which returns even worse speeds of around 500M/bit

edit: title should have been RTL8111E

bledd · 22 Sep 2014 at 22:23

What kind of hard drives do you have? Are they the limiting factor?

Tried another ethernet cable?

Frozennova · 23 Sep 2014 at 07:13

SSD in both machines, irrelevant though using iperf as it's purely network bench doest rely on disk at all

Tried multiple ethernet cables, but as I mentioned in the OP this has to be a windows related issue as I installed Linux mint on a spare drive and performance I'd absolutely spot on.

Ricimer · 23 Sep 2014 at 23:45

Is it actually Windows Server OS? I had a similar issue on a new build, tried everything until I realised speed was fine when push/pulling files from the server rather than the client machine. Turned off SMB signing and it can do 110MB/s fine.

Usually it's not an issue, unless you run a home server, 2008 up will use SMB signing when it can for a *DC*, member servers don't by default.

Frozennova · 24 Sep 2014 at 11:25

Debian 7 on the server.

Nothing to do with SMB as it's not what I'm using to gauge network performance. Iperf is far more accurate

Ricimer · 24 Sep 2014 at 20:07

What was actually slow? What iperf options?

Windows/Windows

iperf -s -i 1 on the server

Client

iperf -c IP will report 865Mb/s on mine
iperf -n 1024M -i 1 -c IP will report 945Mb/s

Frozennova · 24 Sep 2014 at 20:29

Debian/Windows

iperf -s
iperf -c IP -1 -t 30

750Mbit/s

Debian/Mint

same options

950Mbit/s

Debian system has remained the same the whole time, the windows/mint are exactly the same hardware as it's a dual boot.

Ricimer · 24 Sep 2014 at 20:46

Assuming other non iperf tests produce the same results, then there might not be much you can do.

If there is no AV with network scanning, the only things left to try are windows/NIC offload settings, although I've not tweaked anything here and one of the NICs in my iperf test was an 8168, which shares drivers with the 8111E.

Frozennova · 24 Sep 2014 at 21:00

Already tried with anti virus etc disabled. Also tried a diagnostic start too.

Might have to start digging through the NIC settings in device manager then, that or move to a *nix OS on my desktop