In reply to a post by ian72:

I am assuming that iPerf3 doesn't use the HDD at all as I am guessing it just sends a stream of data without reading or writing it from the hard drive. It wouldn't be a good test of network performance if it relied on the speed of a hard drive.

Correct, iPerf of any version does not use the HDD for anything other than loading the program into RAM.

In reply to a post by jchamier:

You�ve reliably missed the end to end part of the equation. The sending machine has to be able to send at 900 Mbps+ which it may not be able if the HDD is encrypted and using CPU to decrypt thus breaking any DMA to the NIC.

I have 950 Mbps from my Realtek NIC. I have more problems with Intel drivers for WiFi than any other vendor. They are awful. The Broadcom NIC�s on enterprise servers are great.

I would point out that I was talking about wired Ethernet not WiFi which comes from a completely different section of the company. Intel wired Ethernet NIC's are widely regarded as excellent, if not the gold standard.

In reply to a post by jabuzzard:

Correct, iPerf of any version does not use the HDD for anything other than loading the program into RAM.

Then the whole performance of the PC, and the impact of non-vendor security software needs to be checked. The likes of Kaspersky, Norton, Bitdefender, and others. Often an uninstall and reboot leaves pieces of the product around.

In reply to a post by jabuzzard:

I would point out that I was talking about wired Ethernet not WiFi which comes from a completely different section of the company. Intel wired Ethernet NIC's are widely regarded as excellent, if not the gold standard.

On enterprise hardware I agree. On domestic grade hardware I've seen issues.

Just back from a week's hols so haven't kept up with this thread, but thanks all for your feedback and info.

I've installed iPerf3 on my NAS and run it as a server then retried the test from my desktop PC. Even with lots of background processes running with the CPU at near 100%, I get just under 950Mbps reported back by iPerf3, so compared with the desktop PC I'm guessing that the Surface Dock has pretty [censored] Ethernet hardware, given the result of around 600Mbps for the test between the desktop PC and docked Surface Pro.

But when I did the same test from the docked Surface Pro and the NAS iPerf3 server, I get 927Mbps, not quite as good as the desktop PC's result but much better than the reported speed between the desktop PC and docked Surface Pro, so the Surface Dock ethernet hardware is respectable enough.

Finally for the sake of completeness, I re-ran the tests between the desktop PC and docked Surface Pro: with the desktop as a server the docked SP reports 458Mbps; with the SP a server, the reported speed is 618 Mbps.

Some info on the network topology: the desktop PC is connected to a Cisco SG300-20 switch which is what everything else in the house is connected to. The Surface Dock is connected to another SG300-20 switch in the office which is connected to the aforementioned main switch so I'm wondering if that might be a factor. Obviously, to check for that possibility I'd need to connect the Surface Dock to the main switch and retry the test, which I can't do until I get a long enough patch cable, which I'll do this week.

Also, although you may know this already - the basic command on the iperf3 e.g. iperf3 -c 192.168.1.26
does an upload from the client to the server.

You can also do a download to the client from the server using the -R switch (reverse)

e.g. iperf3 -c 192.168.1.26 -R

As you may have noticed there is no disk usage while performing the test.

CPU usage will depend on the devices, although my Raspberry Pi 4 only uses 15% CPU while testing.

I get 910 mbps between my desktop and the Raspberry Pi 4 through 2 Netgear GS108 switches.

Edited by mrmarktigger (Mon 03-Feb-20 21:16:53)

It might be worth considering booting from a Linux live CD, that would rule out any issues with antivirus/bloatware on windows.

Good thinking. These days NIC drivers for Linux are now good, in the past I've had issues on server motherboards!

In reply to a post by jabuzzard:

It might be worth considering booting from a Linux live CD, that would rule out any issues with antivirus/bloatware on windows.

That's a great idea, did that and created an Ubuntu 19.10 bootable USB stick, had to download the iperf3 and dependent packages though, installed and ran tests and got 946Mb/s

I'll keep that USB stick handy

Really? What server motherboards are these? With a mixture of Broadcom and Intel and a smattering of Qlogic I have never had a problem with networking on Linux on a server, in >20 years. I have however recalled why Realtek chipsets are at least historically been considered a bit rubbish. The issue is higher CPU utilization than offerings from Intel and 3com for the same throughput, which where considered the gold standard in the timeframe I was thinking about. 3com another acquisition squandered by HP.

There was an issue with some Broadcom server chipsets not doing jumbo packets too, but we ditched the last of our servers with this limitation two years ago now. You would need something quite old for it to be relevant today. Dell rack mounting Precision workstations. They where a bit naff all round. For example the only way to determine which drive in a RAID array had failed was to note the serial numbers of the working drives, power down the server then start poping your hotswap drives to work out which drive was dead. I kid you not. I believe later models in the line fixed this particular deficiency.