LAN throughput weirdness

exoplasm

Ok so my home network consists of more computers than one person should have, but here's how it works:

Main PC: Dual boot XP Pro SP3 and Vista Ultimate SP1
Media Center PC: Vista Ultimate SP1
2 Spare PCs: XP Pro SP3 and [strike]Ubuntu[/strike]borked Mac OS X86
Laptop: Ubuntu

They are all connected to a gigabit switch (aside from the laptop; wireless obviously). The problem I have is that when sending files to my media center PC, regardless of what PC I send from, or if I "pull" the files instead of pushing them, it tops out at about 13 MB/s transfer speed. Now files going from the media center PC to any other tops out at over 30 MB/s. Any of my other PCs can do 20 to 30 MB/s between each other.

I've tried it from every PC (except the laptop) and even my dual boot main PC in both OSes. 13 MB/s is the cap no matter what.

Why does my media center PC only take 13 MB/s for incoming transfers? It's not a hard disk limitation. I have it fully updated with windows updates to fix any file copy issues. Latest network drivers. WTF? Could it be the network cable? I use Cat 5e and Cat 6 for everything.

GrimReaper

Have you considered disabling some qos, ipv6 etc stuff on the media center pc?

Also, what NIC is in the pc? (actual make and model)

If it's something like VIA then there's your problem, if it's Intel or 3com then I seriously doubt there's anything wrong with the network card/chipset.

Have you checked CPU usage during a single large file transfer on the media center pc? What's the MTU for the network card of the media center pc?

sinn

Sounds like the hard disk in the Media PC isn't keeping up. Is it an older disk? SATA or IDE? Your setup sounds very similar to mine. With my main rig being Vista x64 and a media PC running Vista Ultimate 32, both on a gigabit network. Before I swapped in a new (western digital 640GB) drive into the media PC I was only writing to the media PC at about 15 MB/s, reading slightly faster at about 25 MB/s. I swapped in the new drive (which matches the same drive on my main rig) and now get 50-60 MB/s between the two PCs.

Krikee

Try making a patch cable to connect directly to your box to check your speeds sans routers/switches. Check to see if your Media box is auto-negotiating to 1 Gbps.