WinXP Network Speed Question

[LarryG]

A professional colleague has a small (three computers + NAS drive + a couple-three printers) 100Mbs network in his office. His computer runs Windows 2000. His two employees' computers run XP Pro, and both are newer/faster machines than the lone Win2000 box.

The older, slower Win2000 computer opens large files (CAD drawing) across the network virtually instantly, as if accessing a local drive. The two newer, faster XP boxes take 10-12 seconds to open the same files.

Anyone know what might be going on? Is there some setting he needs to look at or change, or is this a "feature" of XP, or ... ???

(I can request more info from my colleague, if necessary.)

[maxparot]

I'd guess that the XP boxes have their firewall set on and it is slowing things a bit. Other than that maybe antivirus could slow things a bit. The intergration of the firewall and antivirus is a bit different from 2000-XP.

[bebop]

first thing is to check for packet loss on the slow machine. I believe the network properties panel will show the number of errors accumulated on an interface.

The most common cause of this I've seen is a bad ethernet cable, often it'll cause 5-10% packet loss and make the network feel slow. Many times it occurs when the interface is set for full duplex but the cable was checked out at half duplex, and it has a problem that doesnt show up at that rate. Have him manually set the interface to 100mbps/half duplex and see if the speed improves. If that doesnt help try changing the cable, or changing ports on the switch.

[LarryG]

I'd guess that the XP boxes have their firewall set on and it is slowing things a bit.

I forgot to mention ... I asked about that, and he says the XP firewalls are disabled.

[wreckwriter]

assuming its a 10/100 ethernet network: Check the properties of the network cards in the slow boxes. See if they're set to 10 instead of 100. Use control panel/system/device manager. Select card, properties/advanced/link speed and duplex (or similar). Should be set to either auto or 100/Full Duplex. If set to auto, try 100/full.

[Tequila]

How's everything wired together? Does he have just one router/switch, or are there a few layers to the network topology? Are all the computers running the same version of the CAD software?

There's a ton of things it could be. The more information you can throw up on the board the better.

[LarryG]

How's everything wired together? Does he have just one router/switch, or are there a few layers to the network topology? Are all the computers running the same version of the CAD software?

One router; all NICs are 100Mbs (he even tried new cards in the two XP machines), and new Cat5 cables. AFAIK the CAD software version is the same on all stations.

I think that before he added the NAS drive, his computer (the Win2000 box) acted as the file server. I don't know whether this problem existed then, or if it's new since the addition of the NAS drive (but I'll find out).

[wreckwriter]

all NICs are 100Mbs

But 100 mbs NICs can also run at 10. Did you/he actually check that they are set to 100? I've seen it happen multiple times where a 100 card gets sets to 10 somehow.

[Tequila]

This might sound like a stupid question: Are the files STILL on his win2000 box by any chance?

[DaveW]

How about the network jacks or the hub/switch jacks? They may be damaged - have you tried swapping the computers (or running the cables between rooms)?

[TJG]

Since I don't see information on it, let's start with basic troubleshooting to narrow the problem. If this has been done, let me know. I'm assuming the drawings are stored on the NAS drive, but correct me if that's wrong. On each computer, open the task manager, and close all running applications. Look at the processes tab, and see if anything is using a lot of CPU (other than the System Idle Process). If there is, you may have a virus, spyware, etc. using up a lot of cpu cycles, causing slow performance.

If all looks good, with all applications closed, sit at each computer and copy one of the large files from the NAS drive and time it. Yes, you will have to open one application (windows explorer) to copy the file. If we see similar results (slow copying to the XP computers, but not to the Win2k computer) we will look at the network. If the results are not the same, however, the network is eliminated.

If it's the network, go to the router where all the computers are connected, try swapping the ports of one of the XP computers with the Win2K computer. If the problem stays with the XP computer, we can eliminate the router.

Next, follow the network cables from the router to the XP computers. Are they near a copy machine, fluorescent lights or other items that can generate a large amount of interference? Interference will cause slow network performance.

These are just a few quick tests, and the last item can be difficult if the cables run through the ceilings or conduits. The more basics we cover up front, the quicker we narrow the problem down. We may find it is a network issue, but if we've done the above troubleshooting, it is most likely the setup of the networking on the XP computers.

[LarryG]

Thanks for the suggestions thus far, everyone. I'll pass them along to my friend and see what shakes out.

[scorrpio]

I believe I know what's going on. XP has something called 'QoS(Quality of Service) Packet Scheduler'. It is a network traffic control that limits rate of data flow and provides prioritization services so that a given machine cannot hog entire network - and that higher priority processes can get hold of network as needed. I also believe XP Pro has it enabled by default. (My work PC that has XP Pro, has it).

It looks like this scheduler is what restricts things. At 100Mbps, you should take about 1 second per every 12MB of file to open it. But if QoS limits the flow, it might allocate only 20% or less of network capacity to this task.

In Control Panel, go to Network Connections, right-click the LAN icon, and select Properties. One of the listed components should be QoS packet scheduler. You can either remove it completely, or you can configure it to 'open up' the bandwidth.

[LarryG]

The mystery continues.

No joy yet, fellas. I passed along all questions and comments to my colleague; here's a verbatim paste of what he reported back:

- All AutoCAD versions are the same for the 3 computers.

- The "Local Area Connection Status" has been checked at each computer and they all show 100.0 Mbps.

- All network cables are Cat 5 rated and are routed through similar locations. Each cable is 50 feet or less in length.

- A test was done using Cat 5e rated cable on one "slow" connection. There was no improvement to speed.

- Windows firewall has been turned off of all computers.

- All computers run Norton Internet Security. The Win2000 computer runs Norton 2005. The XP computers run Norton 2006.

- We have a 5 port hub, a 4 port router, and a DSL modem. All three computers are connected into the ports of the router. When the connection is moved to the hub, there is no noticeable speed change.

- All three computers access the Internet at the same apparent speed.

- The file server used to be on one of the XP computers. When that was the case, that XP computer and the 2000 computer could access files quickly while the remaining XP had slower load time for drawings. After the network attached storage drive was connected to the hub, the 2000 computer could access just as quickly but the XP computers both had slower load time.

- Neither XP computer had QoS installed. However, the 2000 computer did and it has now been disabled. No increase in speed for anyone.

[TheRic]

Try loading the files with Symantec turned off. There are features in Symantec that will scan files coming across a network. It's possible the Win2K computer has that turned off, or the file type on the Win2K is excluded.

It's possible the speed af some of the ports have been changed on the router. Swap the Win2K and a WinXP port at the router. Not move it to the Hub.

Are the IP numbers all in the case group?
Are all computers using the same Domain / workgroup? Check spelling.