Not getting Gigabit, how to diagnose?

[Goi]

Hi,

I have 2 Windows 7 PCs connected via what I think is Cat 5E cables to an ASUS broadband router which is Gigabit capable. The PCs are also Gigabit capable. However, I'm not getting Gigabit speeds. File copies between the 2 PCs top out slightly over 10MB/s, which indicates that it's only 100Mbps. How can I diagnose which link isn't getting Gigabit? i.e. PC1 to router or PC2 to router or both.

Thanks.

 

[ch33zw1z]

Use something like iperf to test the connection between the PC's. That will tell you what you are really getting. 10MB/s is pretty low for gigabit (but high for 100Mbps), but not uncommon for slow disk drives.

iperf works like this:

on PC1, download iperf, open a cmd prompt and cd to teh iperf dir. run iperf -s

on PC2, do the samething, but run iperf -c x.x.x.x (ip of pc1)

I get about 60 MBps transfers between pcs on gigabit, iperf results are about 450-500 Mbps

 

[Gryz]

Something I always wondered ....

When you open the network control panel in Windows, and then click on "Local Area Connection" for your ethernet interface, you get a nice window called "Local Area Connection Status". IPv4 and IPv6 connectivity, Media State, how long connected, and Speed. Example:

Speed on that picture says: "100 Mbps".
Speed on my machine says: "1.0 Gbps".
Would that be the maximum ability of the hardware (giga, fast or regular ethernet) ?
Or would it be the current status of the ethernet interface, after negotiating with the other side of the cable ?

I hope it would be the second option. If so, that would be a good indicator to look at on both PCs.

And I agree that file copies are a terrible indicator of network speed. Usually you are measuring the speed of your harddisks. That was even the case already 20 years ago when ethernet was only 10 Mbps. And HDDs were even slower. I don't think the relative situation changed much.
You need a tool that generates and accepts data on the fly, without accessing any storage.

 

[Fardringle]

The number reported there is the negotiated speed of the link, which means that it should be capable of the listed speed, but doesn't necessarily mean that you will actually transfer at those speeds since interference, bad cables, improperly functioning hardware, slow hard disks, and many other things can affect actual throughput.


I think this is an important thing to look at, though:

connected via what I think is Cat 5E cables

Good quality CAT5e cables can handle gigabit, but old/bad/handmade cables probably won't be reliable enough for gigabit so I'd try new cables to see what happens. (Run iperf as cheez suggested both on the current cables and on the new ones to see what results you get.)

 

[Goi]

Thanks ch33zw1z, I'll try that.

@Fardringle, my 2 PCs are connected to wall RJ45 sockets, and the Cat5E (I think) cables have been in there for over a decade.

 

[jumpncrash]

I routinely get 90+MB/s on large file transfers over my Gigabit network, so 10 is definitely slow, on 100Mbps 10 would be acceptable though, at least that's what I was getting before I upgraded.

I would check your cables in the wall with a spare length that you can run to elimintate the wall runs altogether.

Nick

 

[ch33zw1z]

I routinely get 90+MB/s on large file transfers over my Gigabit network, so 10 is definitely slow, on 100Mbps 10 would be acceptable though, at least that's what I was getting before I upgraded.

I would check your cables in the wall with a spare length that you can run to elimintate the wall runs altogether.

Nick

right, if iperf results are not up to par, then testing without using hte in-wall cabling is the next step.

This is where it's handy to use laptops instead of desktops, to test one wall run at a time end to end.

 

[Elixer]

I routinely get 90+MB/s on large file transfers over my Gigabit network, so 10 is definitely slow, on 100Mbps 10 would be acceptable though, at least that's what I was getting before I upgraded.

I would check your cables in the wall with a spare length that you can run to elimintate the wall runs altogether.

Nick

You must be using a very fast SSD, or perhpas a RAM drive ?
Usually, most people get around 30-50MB/s and that is using a fast HD...

If the properties windows shows speed at 100Mbps, then it isn't communicating at gigabit at all. Most likely you have the computer hooked up to a 100Mbps switch/router instead of a gigabit switch/router.
If you do have a gigabit switch/router and it does that, it is either the cable, or the NIC of that computer is set to 100Mbps instead of 1000Mbps.

 

[jumpncrash]

You must be using a very fast SSD, or perhpas a RAM drive ?
Usually, most people get around 30-50MB/s and that is using a fast HD...

If the properties windows shows speed at 100Mbps, then it isn't communicating at gigabit at all. Most likely you have the computer hooked up to a 100Mbps switch/router instead of a gigabit switch/router.
If you do have a gigabit switch/router and it does that, it is either the cable, or the NIC of that computer is set to 100Mbps instead of 1000Mbps.

I'm using 2 SSDs in RAID0 on my main PC and regular seagate barracuda 2TBs in my server, they could even be western greens, depends which drive I'm transferring to.

I haven't seen HDD transfers that low since 5400rpm 8mb cache drives were common. I run atto on my western black and get over 150MB/s easily, my RAID SSDs get me in the 1000MB/s range. So far it's always the network that is the bottleneck.

 

[Goi]

I haven't tried iperf yet, but under Local Area Connection Status, I only see 100Mbps rather than Gigabit

 

[ch33zw1z]

I haven't tried iperf yet, but under Local Area Connection Status, I only see 100Mbps rather than Gigabit

That's actually a good thing, because you've identified an issue with little troubleshooting. Now you need to find out why.

You have two wall outlets for ethernet, correct? I would recommend switching outlets between the pc's, trying to figure out if it's the pc or the in wall cabling. Try a new patch cable with the pc.

 

[Gryz]

You were copying between 2 PCs. Do both iindicate 100 Mbps, or did you check only 1 PC ?

Go look on the other one too. If the other one says 1Gbps, you know the router is not to blame.

Can you attach the PCs directly to each other (with a short cable) ? Do you get 1 Gbps on both sides then ? That could indicate the problem lies with the cable in the wall.

If you have a laptop (or can borrow one) with Gigabit Ethernet, you can use that to test more. Connect it directly to PC 1. Then PC 2. Then directly to the router. Keep checking at what speeds the interfaces connect.

The only way to figure out what is going on, is to isolate components. By removing other components as much as possible. Just using some common sense. That's basic troubleshooting strategy. Good luck.

 

[drebo]

If the router does actually have a gigabit switch in it and your PCs are negotiating 100mbps, that means that your cabling is to blame.

Possibly it's actually only CAT5 and not CAT5E (over short distances, that doesn't really matter, but you haven't given us distances) or it's been physically damaged.

Maybe call someone out to certify the line and if it's broken, repair it?

 

[JackMDS]

I haven't tried iperf yet, but under Local Area Connection Status, I only see 100Mbps rather than Gigabit

Any computer that shows in the status 100 Mb/sec. is actually telling you "Hey Dude what do you want from me I can Not currently run Giga".

I.e., make your computer Giga capable first.

 

[Goi]

The PCs are both Gigabit capable(1 Sandybridge, 1 Ivybridge), and so is the router (ASUS RT-N15U)

I'll check on the cables. I don't have a laptop though so it's gonna be challenging.

 

[Goi]

Mystery solved! The cable from the router to the wall jack was the culprit. Switched it to a Cat 5E cable and now I'm getting Gigabit, woohoo.

Luckily it wasn't the in-wall cables, that would've been a b*tch to fix, phew!

 

[ch33zw1z]

Mystery solved! The cable from the router to the wall jack was the culprit. Switched it to a Cat 5E cable and now I'm getting Gigabit, woohoo.

Luckily it wasn't the in-wall cables, that would've been a b*tch to fix, phew!

cool! good job man.

don't worry too much about replacing the in wall cables. it's easier to pull them since there's already cable in place that can be used to pull the new cables. It's a bitch when you fishing cable through the wall for a new run.