I upgraded my home LAN to gigabit, and I'm not getting the speeds I expected. Not even close. Just wondering if anyone else has run in to this or has any ideas.

Transferring a large file from one computer to the other used to go at about 8-12 Megabytes/sec. Upgrading to gigabit, I was expecting 10 times that speed. In reality, what I'm getting is 16-20 Megabytes/sec, according to Windows 7 file transfer thingy.

Ive since done a ton of research on the various hardware components involved and I now know that due to various bottlenecks, I shouldn't really expect 80-120 Megabytes/sec. Instead I should be happy with 40-60 Megabytes/sec. Ok fine. I would be happy with that. But my current rates are still way below that.

Has anyone else experienced this? From what I can tell, I definetly do not have anything bottlenecking things way down to 20 Megabytes/sec. I have googled this and found a few other folks having the same issues, but no intelligent answers.

Hope someone has a good idea. I'll provide more specs if asked, but theres really no surprises. Gigabit Router, Cat 6 cables, Gigabit NICs/ gigabit onboard cards, 7200 RPM HDDs... transfers should be much faster!

My understanding is that there can't be any 100mbit devices on the network otherwise the whole thing shifts to 100mbit. Hopefully someone will correct me if this is wrong, but I have seen similar problems in mixed speed networks.

Possibly limited by hard drives. I have an SSD on one computer and a RAID5 of 3x750GB 7200RPM drives on the other and I get 50MB/s copying to the RAID5 and 75MB/s copying to the SSD.

I plugged my X360 (which is a 100 megabit device) into my switch and speeds between my PCs dropped a tiny bit (I get 40ish MB/sec now), but I still easily exceeded 100 megabit speeds.

Perhaps the 100 megabit limitation only holds true for hubs, and not switches?

[Edited by - Nypyren on November 16, 2010 12:23:19 AM]

See if you can find a test program that literally pumps data across the network without waiting on hard drives etc. I'm sure someone has written such a program that prints the transfer speed.

I get some promising looking results from here.

I upgraded a friends network to gigabit a couple of years ago, although I used Cat5E but had the same issue. I wrote a small application (apologies I don't have it to hand any longer) that just transferred random data from one PC to another and found the speed to be just right, yet transferring data from one HDD to another over the network slapped the speed right down; obviously I cannot say for definite but in my case the HDD just couldn't keep up.

I also had the same problem when upgrading to gigabit a few years ago. Seems support for gigabit is really bad. I remember at one PC i could send UDP at 999MBit but an older PC would only receive 30%, while two newer PCs reached about 70% on the same network. I also Googled and found that Vista had some new TCP handling that could interfere with things.

One thing you can try is opening the properties for your network card in the Device Manager, and under Advanced there should be a Jumbo Frame feature and some other settings that you can try enabling or disabling. That can increase the speed quite a lot.

Quote: Original post by rip-off
See if you can find a test program that literally pumps data across the network without waiting on hard drives etc. I'm sure someone has written such a program that prints the transfer speed.

I get some promising looking results from here.

Not to hijack the thread but how did you find out about SSL Google? Awesome.....

Quote: Original post by tstrimp
My understanding is that there can't be any 100mbit devices on the network otherwise the whole thing shifts to 100mbit. Hopefully someone will correct me if this is wrong, but I have seen similar problems in mixed speed networks.

I *think* what that means is there cant be any 100mbit devices between the 2 computers you are transfering between. This is pretty obvious if you think about it. I think if there is a third computer thats only 100mbit, that doesnt affect the transfer speed between the 2 computers that ARE.

In any case, I have tested the transfer with all my computers OFF except for the 2 in question. Both have gigabit cards, all wires are cat6, and the Router is gigabit of course.

And remember, I saw speeds of about 18 Megabytes per second, which is about 144 mbit, which is well over 100, so I dont think the network is reverting back to 100mbit.

Quote: Original post by Nypyren
Possibly limited by hard drives. I have an SSD on one computer and a RAID5 of 3x750GB 7200RPM drives on the other and I get 50MB/s copying to the RAID5 and 75MB/s copying to the SSD.

I dont have SSD or RAID or anything fancy, just regular old 7200 RPM SATA drives. However, the transfer speed of these drives is supposed to be around 125 Megabytes/sec. Thats a theoretical maximum, more realistic speeds are around 80 Megabytes/sec. This is still way way higher than what I'm getting. I dont think the hard drives are the bottleneck.

Besides, I have an external USB hard drive, and I get transfer speeds of about 35 Megabytes/sec. So even if the hard drives were a bottleneck, I would expect at least 35 not 18 like I'm getting.

Quote: Original post by rip-off
See if you can find a test program that literally pumps data across the network without waiting on hard drives etc. I'm sure someone has written such a program that prints the transfer speed.

I get some promising looking results from here.

Good idea, will try that tonight. Thanks!