Really strange network speeds after upgrading to gigabit.

[Zagor]

I have a fairly large media server (1.5 Terabyte on RAID5). Since I transfer fairly large files (anywhere between 1 to 20 GB in size) I decided that I would upgrade to a gigabit network. I am aware that, at best, I would gain about 2 to 2.5 times the speed of a 100Mb network (I was hoping for about 30MB/S). I purchased 3 TrendNet PCI NIC cards along with an SMC switch that supports large frames. I installed the NICs on two clients and on the media server. Transfers between the two clients are what I was expecting (about 25MB/S) the strange issue comes to light when transfering files to and from the server.

At first I was only getting half the performance of a 100 Mb network (about 5MB/S), after spending several hours tweaking and troubleshooting, I got nowhere. When I switched to the onboard 100Mb NIC I would get the standard 10MB/S but the added gigabit NIC would only yeld half that.

Just by chance I happened to move the mouse around (on the server) during a transfer and all of a sudden the transfer rates jumped up dramatically. To make a long story short, if I move the mouse pointer around the screen (while tranfering) I get the expected gigabit speeds, as soon as I stop moving it around it drops down to half the megabit expected speeds. This was very consistant and repeatable.

I then also discovered that if I had internet explorer open and the usatoday.com main page displayed it would yeld the same gigabit results (25MB/S) without having to move the mouse pointer around. If I minimized the IE window it would drop down to 5MB/S and would not go back up until I maximized IE. I tried using Firefox but it did NOT yeld the same results, it just stayed at 5MB/S. When I tried PCATTCP utility (memory to memory transfers) I got the same low results of 5 MB/S if IE was not running and maximized with the usatoday.com web page displayed but got much higher results (50MB/S) if the opposite was true.


Anybody have any ideas on what might be causing this?

 

[Lemieux66]

Sounds like the gigabit nic on the server is sharing resources with your video card or some other device. I'd try moving the nic to another PCI slot.

 

[Zagor]

I thought that might have been the problem also so I moved the card around to other PCI slots, I even swapped out the NIC card with another one, no difference.

To make matters even worse this only happens in one direction from client to server, the other way around works fine and it doesn't matter which computer initiates the transfer.

I just finished re-installing winxp thinking that maybe it was a software issue but it didn't help any. Exact same problem. I guess i'll just keep IE open to a webpage with some flashy graphics (a text one won't work). Also, I was wrong when I said that it didn't work when IE was minimized. It does work even if IE is minimized.

 

[spikespiegal]

To get a grasp of the problem:

Your "server" is Windows XP, and you see the speed issues only if you are sending files to the server. You've tried other gigabit cards.

What happens when you log off the server and transfer files to it with nobody looged on?

Have you tried forcing the card to manual speeds?

Try turning off power management utils and options.

 

[Zagor]

Yes, the "server" is running Winxp Pro. I haven't tried transferring files while logged off but I'll give it a shot this evening.

I have tried setting the speed manually but no difference, I also tried different jumbo frames sizes including disabling them, no difference.

The speed issues are files being transferred to the "server". From server to other desktop speeds are much better (not great but better). When I am transferring from 'server' to client I get speeds that alternate (almost like a heartbeat) between 15 and 28 MB/s (looking at a transfer speed graph it looks like a zig-zag). When I transfer from client to server and IE is not open and I don't move the mouse, transfer speeds are a steady 4-5 MB/s. As soon as I move the mouse pointer it jumps up to 15-18 and as long as i keep moving it it stays up there. As soon as I stop it drops down to 4-5. Opening IE and displaying a flashy webpage makes the transfer speeds jump up to alteranting between 15 and 28 MB/s.

Moving the NIC to different PCI slot has not helped. Replacing the NIC with another one (although exact same model) has not helped.

The "server" is just a 2.4 P4 on a Asus motherboard (P4S800, I think) with 512MB RAM. BTW, it makes no difference regardless if I am transferring to the RAID or to the C: drive (a 40GB IDE drive). The RAID controller is a HightPoint RocketRaid 1820a.

 

[Zagor]

Well, I tried your suggestions and I did get some positive results. When I transfer files after a reboot and nobody logged on I get the speed I should (I am transferring a DVD ISO image 4.3GB). I get an average rate of 22MB/S with a max of 29MB/s. The weird thing is that this speed is only good for the first file transfer any subsequent transfers and it drops down to the 4-5 MB/s rate. The good news now is that when I move the mouse around on these subsequent transfers, the speed jumps up as before but when I let go of the mouse it only drops down to about 13-14MB/s instead of the 4-5 it was doing before and it will stay there until the transfer is finished. After a reboot once again I get one fast file transfer and the rest start slow and remail slow until I move the mouse around and once I release the mouse it will settle around 13.

Again, this is with a fresh install of windows xp with sp2. No other updates. I just added two registry keys (set TcpWindowsize to 131400 and tcp13230pts to 3) as I have seen recommend on several tweak sites.