Slow LAN....why?

Question

I have a Dimension, P3 600 XP SP2, on my home LAN that when it does a backup to a network harddrive on the LAN, it only outputs data at about 10 megbits/s or about 10% of the LAN utilization and 100% CPU utilization. This is with no other activity on the LAN. And this is doing drive image backups using Norton Ghost 9.0. Alo 2 other Dimensions P4 3Ghz XP SP2, when doing the same backup operate at about 30megbits/s or about 30% of LAN capacity and less then 50% CPU utilization. I have even swapped out the LAN card for a brand new and different brand and set it for 100 duplex and still no improvement in trasfer rate. Is there something I can do to improve the LAN transfer rate from the P3 PC? Is it just that it take so much processing power to send ethernet data that its slower CPU cant put out data like the other 2 faster P4s?. If so, It surprizes me that it utilizes so much CPU cycles. thanks for any insight

jmwills · Answer

Is there a switch or router in between the two PC's?  And if so, is it a 10/100 switch?? Message Edited by jmwills on 02-13-2005 11:29 AM

rkruz · Answer

Yes. there is a switch and a router.

Router is Linksys BFESR41 (cable modem router)
Switch is DLINK DSS-5+..

All 100baseT and newly purchased this year.

There are 4 PC, 1 printer and one NAS on the LAN.
During backups though, the only things active are the NAS (Network harddrive) and the PC being backed up.
Also, during backup the harddrive access duty cycle is only about 10% so thats not the bottle neck. Im might have a limit of about 30megbits/s due to the NAS (I say that only becuase the other 2 PC transfer at that rate) but still the P3 will only get up to 12-15 Mbps at best.

rkruz · Answer

I guess its about 30mbps...like I said in the previous post....becuase two other p4 PCs on the same LAN, doing identical backups with identical software operate at about 30 mbps vs the P3 which again is at max about 15mbps. Taking the Ghost processing out of the equation by just doing a simple file transfer....the P3 is about 15mbps and the p4 is about 30mbps..or the same.....so I can only conclude thats is the slower P3 that is the bottle neck. totally surprizing that the CPU has do do so much processing for simple data transfer on LAN. Sounds like an area for big improvement in hardware.

jmwills · Answer

What are the read/write specs on the NAS?  The data can only move as fast as the destination will allow files being written to.

jmwills · Answer

Do you have these backing up at the same time?  The speed of one machine has nothing to do with the speed of the others on the LAN.

jmwills · Answer

Well, thats why the BUS speed of the P3 is taking so long to process the data. Your problem has nothing to do with LAN speed rather the inability of the P3 to process data as fast as a P4 which is to be expected.

I mean , the speed your talking about is probably 400% fater than your outside connectioon and unless your backing up massive amounts of data, I fail to see the big concern here.

rkruz · Answer

no....like I said in the previous post.....only one is backing at a time.

The P3 is about 1/2 as fast as the P4s, even when I do a direct PC to PC transfer to that from P4 to P3 machine, and bypassing the NAS, it is still about 15mbps or less and that P3 is 100% of CPU utilization. So all the evidence points to the P3 and really a system that uses excessive PC cycles to process simple data transfer.

Networking, Internet, & Bluetooth

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