Strange upload behaviour

[peperj]

Hi there folks,

Hope someone can help me understand what is happening here.

SITUATION

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Computer is Core 2 Duo, 2 GB RAM, CPU is around 10% busy, 13% tops.

uTorrent 1.7.7

Link is 20/5, very fast, very reliable.

private tracker.

3 downloads, plenty of seeds. Each download can, ISOLATED, use my whole download capacity.

1 upload, 41 leechers. Upload speed is around 370KB/s when seeding without downloading.

max speed is defined as download 2200 and upload 450. Plenty of spare bandwidth for protocol control.

Windows Vista, WRT54GL Router with Tomato firmware.

PROBLEM

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If I activate all 3 downloads simultaneously, my upload speed immediately goes down to around 100KB/s. CPU is still at 13-14%, memory is at 53% or, in other words, I still have plenty of computer power do deal with the 3 down / 1 up simultaneously, but the upload speed just goes down.

If I cancel 2 downloads and work with just 1 down and 1 up, speeds go back to max. That's the situation as I write this message and upload speed is around 380 kB/s, download at 2.2MB/s. So, everything is fine.

If I add the second download, everything stays fine. But as soon as I add the third download, the upload speed goes down.

CULPRIT

======

I use a 500 GB disk, 32MB of cache, very fast, but I suspect this might be the problem. Haven't done any calculations, but it's the only thing I can imagine might be causing me problems. My cache settings in uTorrent are default. Never messed with these parameters. Should I?

I also checked the router CPU. With 3 downs / 1 up, it stays around 53%

With 2 downs / 1 up, it stays at 55%.

IF I UPLOAD ONLY

=============

Router CPU stays at 30% and upload speed goes all the way to the max, 450 KB/s

QUESTION

========

Would you know why my upload speed suffer when I'm downloading 3 torrents? I have plenty of cpu power, memory and bandwidth to do that. But upload efficiency is affected.

Can the disk I/O be the problem? Any suggestion on how to fix this?

Thanks

PP

[jewelisheaven]

Missed a trash post.

[Switeck]

Have you tried the v1.8 beta which can disable Window's caching of uTorrent's ram cache?

Also, try increasing uTorrent's ram cache to 100 MB.

[peperj]

Yes, same behaviour with the betas. Sorry about the multiple submissions, but I was getting an error message.

[jewelisheaven]

They trashed the wrong post:(