Speed spiking on local area network

[krimms]

Hi,

I've got a problem for which I need a solution. The situation is this:

My computer is one of eleven on a local network. Our connection is fast (100MBit) and the server is running 2003 server edition. I don't think our ISP (asahi-net, Japan) is limiting our connection.

Of the eleven computers on the network, 5 are running utorrent and all have the same problem; uploading and downloading is much slower than it was in the past, but regularly (every 15-20 minutes) it jumps up to normal speed for a second or two, and then drops back down again. The up/download speed graph looks like a flat desert with regularly spaced, very steep volcanoes!

Has anyone encountered this kind of thing before?

I've considered that the connection is maxing-out and have tried limiting the up/down speed on all 5 utorrent computers but the same behaviour continued, but within the limits I'd imposed. I've also tried disabling DHT on all 5, but again it did nothing.

Any help would be greatly appreciated.

[Switeck]

What are the limits set on the other computers?

Probably at regular intervals the speeds are 'rebalanced' for all the computers and while they're being rebalanced everything is given a brief moment of unthrottled speed...although the resulting overloads have to be atrocious.