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Advanced techs only: Gbps Network bandwidth maxed out at 50%

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January 3, 2013 5:59:48 AM

Hi guys,

I have multiple, multi drive PC's connected by Gbps Ethernet.

I have tried transferring data from multiple independant drives on both machines (i.e. from drive b on machine a - drive b on machine b +
from drive c on machine a - drive c on machine b) Note neither of these machines are copying from or to the C:\ , but seem to be restricted at about 50% network usage on both machines. The more drives I copy/paste from, doesn't seem to allow me to stretch the network muscle any further. I have an SSD system drive on each PC and both have significant horsepower (spex below)

Machine A.
ASRock 990FX 16GB RAM 128SSD FX8150 Secondary disks: WD Black 1TB x3 (non RAID)
Machine B.
Gigabyte 790FX 16GB RAM 128SSD PII 955 WD Black 1TB x3 (non RAID)
Both run Win7 64bit.

I have tried using a crossover cable and a Gbps router but the same symptoms exist.

I have checked resource monitor plus a few 3rd party solutions, but there appears to be not be any bottlenecks. The drives are not hitting their limit, and files being copied have ranged from small photo and video files, right up to whole Virtual machine images, just to test what the issue may be.

I am appealing to the community for any experience with pushing consumer grade Gbps to it's limit and any potential causes/fixes to this issue.
January 3, 2013 6:17:02 AM

I'm sure your SSDs won't be able to max out a Gbps network.
SATA 3 SSDs run max at 550Mbps (hence the 50% Gbps network utilization)

If you were to RAID0 a couple of SSDs (in both machines) you would be able to max out your Gbps network.
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January 3, 2013 6:20:58 AM

But adding more disk does not add load to the network, instead, they just seem to start interleaving data. I.e. 1 disk is actively copying, the other is idle, then vice versa.
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January 3, 2013 6:33:30 AM

Yup, full duplex with jumbo frames enabled.
I understand the bandwidth loads HDD's and SSD's have, but no matter what combination of load i try and instill on the network, I can never exceed 50% load. That is the real problem.

I have just tried running a similar copy using RAM disks on both machines, and the same symptom exists. Is it maybe a limitation of Win7 Pro?

I use a lot of Virtual machines, and knowing that I cannot utilise more than 50% of my network bandwidth is a cause of concern for me. Hence me asking you lot.

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January 3, 2013 6:48:00 AM

That is what I just tried. Still capped at about 500Mbps.
I have both Cat5e and Cat6 cables in less than 2m lengths, so cabling should not be a problem.

Might have to get a few additional GbE cards and hope I can team them. Recommendations would be greatly appreciated.
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January 3, 2013 8:31:19 AM

What about QoS settings? + network over heads. or maybe try something like iSCSI.
Also what version of SATA is running, i cannot tell from you OP.
http://technet.microsoft.com/en-us/library/ee338480(v=ws.10).aspx

I found this what may shed some light on the problem:
http://web.forret.com/tools/bandwidth.asp?speed=600&uni...


And something to look at is ASRock XFast Lan utlity, its seems you can set limits and tweeks to network speed. maybe its not installed or is installed but incorrectly configured.
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a c 374 G Storage
January 3, 2013 11:10:07 AM

Have you tried using a lan speed test that doesn't utilize drives at all. Windows will treat a ram disk like any other disk during a file copy so that won't help much. Windows file copy has always been slow. You can try FTP'ing between machines or use some other method to push data across the wire.

I just found this by googling so I don't know how accurate it is, but is says it can bypass drives to check lan speed.

http://www.totusoft.com/lanspeed.html
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January 3, 2013 11:27:34 AM

I haven't seen this much idiocy in a while. You are all confusing Mbps with MBps. MB is megabyte, where as Mb is megabit. 1 Byte equals 8 bits, so 8Mb = 1MB. SSD speeds are measured in MBps, where as networking is measured in Mbps in most cases. 1Gbps Ethernet is 1000 Mbps, or 125MBps. Windows' file transfer dialog measures transfer speeds in MB/s, which means MBps. The realistic maximum that you will get with a Windows file transfer over a local network is around 110MB/s due to overhead. The only way you will get that is if both computers have newer Intel gigabit network cards. You can get them on Newegg for $20-$30. Network chipsets made by companies other than Intel will often max out at a much lower speed, often around 40MB/s.

I have actually found that enabling Jumbo Frames decreases network performance. YMMV.

Any newer 7200 RPM 3.5" drive should be able to push at least 100MB/s for sequential reads and writes, with higher end server hard drives able to do up around to double that. Just about any SSD should be able to max out gigabit Ethernet all by its self.
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January 3, 2013 11:49:54 AM

purrcatian said:
I haven't seen this much idiocy in a while. You are all confusing Mbps with MBps. MB is megabyte, where as Mb is megabit. 1 Byte equals 8 bits, so 8Mb = 1MB. SSD speeds are measured in MBps, where as networking is measured in Mbps in most cases. 1Gbps Ethernet is 1000 Mbps, or 125MBps. Windows' file transfer dialog measures transfer speeds in MB/s, which means MBps. The realistic maximum that you will get with a Windows file transfer over a local network is around 110MB/s due to overhead. The only way you will get that is if both computers have newer Intel gigabit network cards. You can get them on Newegg for $20-$30. Network chipsets made by companies other than Intel will often max out at a much lower speed, often around 40MB/s.

I have actually found that enabling Jumbo Frames decreases network performance. YMMV.

Any newer 7200 RPM 3.5" drive should be able to push at least 100MB/s for sequential reads and writes, with higher end server hard drives able to do up around to double that. Just about any SSD should be able to max out gigabit Ethernet all by its self.


The OP never mentioned his speed, only that he is only getting 50% of network speed which I assume he either got from the network tab in the task manager or by using the resource monitor. When I use either of these references on my gigabit network, I easily get 80% utilization. FTP seems faster than a windows file copy as windows seems to try and buffer data or something which causes regular swings in the network graph. Using FTP the nework graph is more flat.

Anyhow, I'm not saying the OP isn't confusing Mb with MB, but I know most of us already know this difference.
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January 3, 2013 12:06:00 PM

Hawkeye22 said:
The OP never mentioned his speed, only that he is only getting 50% of network speed which I assume he either got from the network tab in the task manager or by using the resource monitor. When I use either of these references on my gigabit network, I easily get 80% utilization. FTP seems faster than a windows file copy as windows seems to try and buffer data or something which causes regular swings in the network graph. Using FTP the nework graph is more flat.

Anyhow, I'm not saying the OP isn't confusing Mb with MB, but I know most of us already know this difference.


+1
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January 3, 2013 12:13:14 PM

Quote:
I'm sure your SSDs won't be able to max out a Gbps network.
SATA 3 SSDs run max at 550Mbps (hence the 50% Gbps network utilization)

zander1983 is confused about the difference between Mbps and MBps.

Quote:
SSDs might be able to max out a Gbps network, but normal HDDs will not.

zander1983 again stating that he is confused about the difference between Mbps and MBps.

Quote:
That is what I just tried. Still capped at about 500Mbps.

Here is the original poster clarifying what he meant by 50% utilization. He is one of the few here who does not seem to be confused about Mbps and MBps, or at least got it right in his post.

I guess that it is just zander1983 who is confused.
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January 4, 2013 1:39:51 AM

Hi guys, thanks for the interest and recommendations for this issue.

For the record, anyone who refers to a NIC as a GbE, surely knows why they are using a lower case b.

I have spent another day googling and trying various different solutions to stretch the legs of my GbE. I have found that with FTP, I get around 530Mbps, which makes sense since it has a lower overhead than windows file copy.
I tried disabling jumbo frames as mentioned earlier but still seem to be capped at or around the 50% mark...
My 990FX runs on SATA 6Gbps, the 790FX 3Gbps, but with either of them more than capable of saturating a 1Gbps link, I don't see there would be a problem.

I have used the Asrock Xfast lan utility, but find it a bit flakey so don't bother with it anymore.

I have ordered a couple of PCIe GbE cards, which I will use to test if it is the OS/Software combination, they are cheaper than the time I have spent on this, so have nothing to loose.

I'll keep you all posted as to how I get on.
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