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Gigabit network bottleneck

Last response: in Networking
December 1, 2009 9:39:20 AM

hihi. just wondering about a gigabit networking issue.

some1 asked me a while back and i don't have an answer.

a gigabit network between 2 dual-core systems with linksys gigabit nics, direct CAT-6 cross cable.

the transfer rate is maxed at around 200-300mbps, even with jumbo frame enabled. can't remember exact figure.

benchmark with iperf.

where are bottlenecks?

thx in advance :) 

December 1, 2009 1:25:32 PM

Check disk fragmentation and Anti-virus settings. Let me know if that helps, also see if you have IPv6 running on both machines.
December 1, 2009 11:45:44 PM

IPv6 not used. just IP4.

On clean install XP SP3.

Not sure about AV. I think it was NOD32.

Non-server or workstation class motherboard with only 32bit PCI. Standard desktop boards on both PCs.

thx for reply.

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December 4, 2009 7:37:53 PM

Disk read/write access could be an issue. If in RAID-0 it may help a little.

Within Windows you can use the built-in Perf monitor to check things like CPU Utilization, Network Utilization, Disk Read/Write (IO) times.

December 5, 2009 1:51:37 PM

My suspicion is somewhere along the bus, board or hdd IO throughput.

32bit PCI technically should be sufficient to handle that speed.

This question has been bugging me for a while. so i guess i'll just have to setup actual test platforms.

thx for the suggestions.
December 20, 2009 3:45:17 AM

It's the BUS IO.
January 8, 2010 7:43:30 PM

It is a mystery bugging me for months...I have two new Win7 laptops hardwired via cat6 and the max transfer speed I am getting is 20Mbps. Where is the bottleneck ..could it be the HD I/O speed?
January 9, 2010 4:44:35 PM

I can't say my suggestions is valid for everyone, but my suspicions center around the 32bit PCI bus and data pathways.

I used RAM-to-RAM benchmarking without any hard disk, it's around 30Mbps. Occasionally maybe 40 but cannot sustain at that level. Tried Jumbo frames as well.

I only got a single 64bit PCI Bus system waiting for another 1 coming in a month or so, and didn't have time to do more tests.

What i want to do is test with PCI-Express Gigabit NICs.

The limitation problem is on the Board.
January 9, 2010 4:46:05 PM

It's not the Cable. I got Cat6 STP running around my house :) 

It's not solely some Registry or MTU issues.

Hard Disk can be a problem, but not significant enuf.