Windows network transfer issue - disk caching?

Hi guys
I'd like some thoughts on a problem I have with one of my Dell Optiplex machines.

I only use it for media streaming to 3 media boxes, network storage, fax and occasional p2p use for large downloads - at 1.5A it's the lowest power system I have to keep on 24/7

The problem is, when pulling large files off it (5gig+) it cannot maintain a continuous transfer rate. It will transfer at ~70mbps for about 10 minutes then stall for about a minute before resuming the transfer. Sometimes though it will cause failed transfers to the requesting machine "Network path no longer available")

When stalled, I notice there is continuous disk activity, as though it is too busy to keep the file transfer going?

I've defragged the drive, it is only 40% full (1.5tb drive)... any ideas what could be causing this problem, what could Windows (XP Pro) be upto every ~10-15 minutes to thrash the drive?

*To rule out hardware, I've transferred the HDD to an identical Optiplex base unit and the problem still occurs.


Cheers guys

[MovedGoalPosts]

Antivirus scan? Windows indexing? Can't see why a cache on the Optiplex would be an issue unless you are writing to it.

It has no special settings on the system, no specific optimisations, just plain XP Pro. It *does* have Symantec Endpoint Protection AV but so do my other machines without the same problem. I'll try disabling it and test again just to see.

---------- Post added at 15:42 ---------- Previous post was at 14:13 ----------

No joy with that project; with AV disabled there is a 10mbps speed gain (~80meg transfer rate) but it still stalls. Have also tried DU Meter and all background apps quit such as streaming server controller and Winfax pro.

So... it remains a mystery.

I opened the Task Manager and during the time of the HD thrashing the system is actually 97% idle with no spikes in page file use etc... but obviously something intensive is going on somewhere.

[Pauls9]

If you enable all the disk operation columns in Task Manager, you'll be able to see which processes are doing the disk thrashing. Might help.

Pauls9 thanks for the tip, I enabled the extra columns but the problem is during the 'stall time' the Task manager window actually freezes for a time also.

I timed the disk thrashing to a little over a minute with no bytes at all being sent across the LAN from the machine (which probably explains the timeouts on Network locations on other machines trying to read from it).

I've re-loaded NIC drivers, swapped network cable, still stalls... <pulls hair out>

[ZrByte]

Which optiplex is it?
Have you tried a reformat?

[DocDutch]

What are the specs on the machine you are transferring files to as data transfer also gets cached in the memory before transmit onto the drive.

and have you got more data on the network you are running sounds you are running a Gigabit network?

Last night I tried to re-install XP just to clear any problem with Windows but there is a problem with the HDD itself I believe. The partition format actually got stuck a few times and even during the XP install the installer locked up for a similar period to the stalling when reading from the drive.

So, I'm hoping whatever is wrong with it will hold out until I can manage to retrieve the data off the other two partitions.

Controller fault? While in my usb dock (after I'd pulled it out of the machine) I noticed a few unusual sounds so it can't be healthy!

I've raised an RMA with Western Digital and they're sending a new drive out in advance (they pre-authorise your credit card as a deposit while they wait for the failed unit) so I don't mind.

Thanks guys for your help!!