Only getting 2.5g Network one way

[neko77025]

So , I can only achieve 2350(ish) Mbps DL from my server, UP seem to Cap around 1320(ish) Mbps. I can see this with both iperf & Open Speed Test. ( have tested this both ways, (ea as Sever or Client)). The out come is always the same .

MAIN PC (HOST) ---to--- Server (Client) (Downloads 1300 / Upload 2400) Mbps
Server (HOST) -- to -- MAIN PC (Client) (Downloads 2400 / Uploads 1300)Mbps

The Network from Main to PC to Server is as so.

Main Gateway is A Cloud Gateway Max , with 2x Flex 2.5Gb switches .. The sever and Main PC have their own Flex 2.5G switch. My main has A realtek 2.5GbE built on the Motherboard, The Server has A Duel Intel I266-V. (Ea PC needs its own switch, run VMs with NIC passthrough , if you do Vitural NIC speeds on both host and Client cant achieve max)

Both PCs are windows 10 Pro, all cables are A min of CAT6 and not very long runs.

What I know.

1) All Drivers up to date (Both M & S) (and Windows)

2) Rolled Back Drivers (Both M & S), [did not help, Undid this]

3) Test / changed out all my cables, Including the Wires in the walls ..(just ran cables, across floor)

4) Removed all my VM NICs, (had issues with HyperV, in the past)

5) I have used 10Gbe in the past with same cables, same PCs .. but were using 10gbe NICs) So ... sure the cables were good.

6) Both M/S are on Default Network (No VLANs between them)

7) Both M/S NICs show up as 2500/2500 (Mbps) in Windows and Unifi

8) Both M/S have NVMe Drives that will achieve 2500+ Mbps



Right now .. I am leaning toward one of the NICs being bad.

Anyhow , if anyone has any idea or what I can test. The main reason I want the 2.5gbe is for uploading to the server and thats what is not working.



(UPDATE)

After thinking about it more, I determined , I truly could not tell if was the Main PC vs Server that was the issue with .. just the 2 PCs.

So I added A 3rd Mini PC with A USB 2.5 Realtek Nic. Ran if off the Main PC Flex 2.5 switch and it got 2.4(ish) both ways. Ran it off the Server Flex 2.5 and again had issues with low uploads (Sub 1.4gbe) (also noticed the downs were a bit lower).

@ this point I can assume the Issue is the Server side / Server switch...

(going to skip the server switch and test that )

(UPDATE 2)

Installed A realtek 2.5 nic into server (removed the dual intel)

Same issue ..2424 Mbps Down , 1437 Up

(UPDATE 3)

Skipping Server 2.5gbe Flex did nothing.



Assuming @ this point is something with the PC.. A setting or something I am not sure ... Any ideas

 

[anonuser57]

The best I can think of is to check for traffic scanning on the gateway.

 

[Wirko]

Do modern motherboards (and network cards) still have the cable testing utility? Try running that on each computer, with the ethernet cable connected at both ends, then with the cable disconnected at the remote end. It might reveal something suspicious, and if the cables are known good, then there's some failure in one of the NICs.

 

[neko77025]

Do modern motherboards (and network cards) still have the cable testing utility? Try running that on each computer, with the ethernet cable connected at both ends, then with the cable disconnected at the remote end. It might reveal something suspicious, and if the cables are known good, then there's some failure in one of the NICs.

I am sure its not any of the cables ... .. I assumed it was A cable at first .. but Ran cables across the floor .. just to make sure it was not even the cables in my walls .. .. changed out patch cables and any cables that could be .. results. Also .. later on I added A 3rd PC with A USB 2.5gb to test speeds .. because I really could not tell witch of the PCs were the issues ... after seeing the 3rd PC and main pc were good ... I test vs the Server .. could tell it was on server end.. I then took the Cables that went to Sever and used them for the 3rd PC ... again the 3rd PC ran 2500 both ways .. so its has to Be something with the Server.

The NIC or A setting ... maybe A program ...