Transmission slows down everything on network

[Runamuck]

I've used search, here and on Google. I've seen a fair number of posts on this topic. I've tried all the tricks, even the "voodoo" ones that shouldn't really do anything but seem to help. But here's where I am.

I am running:

Transmission v1.75 (9112)
Mac OSX 10.5.8 on a MacBook Pro. All updates current.
Connected both Wireless and via Ethernet (have tried both ways, no difference) to a 2-Wire 3800HGV-B Gateway. My ISP is AT&T Uverse. I have 18mbs down/2mbs up service.
I have successfully set up port forwarding on this router, and Transmission "sees" the port as open (green dot).

I am attempting to download a Linux image distro. I have a different torrent client on my Win XP box. It is connected, also wirelessly, to the same router. It uses a different port but that is also forwarded successfully. I won't go into that setup as it works and works very well but that is not my primary machine. My Macbook Pro is my primary work machine and I'm running Transmission on that. Except for some side by side testing, I don't have both boxes running simultaneously.

While running Transmission on the Mac, and attempting to download this file, I get approximately 100-125K down and 200K up. It fluctuates a lot, can drop to 0k both ways several times over the course of an hour. But it averages in that range. I've got download and upload both unchecked, although I've tried the "voodoo" trick of using the throttling (turtle) function and capping down at something like 1000k and up at 200k. It doesn't matter, this is my speed regardless. For comparison, on my Win XP box downloading the same ISO image with almost the same number of shares/seeds, I get consistent 14.5-15.5Mbs download speeds and max out upload at around 1200K.

So my first problem is in trying to understand why Transmission is so slow downloading the same file over the same internal network.

However, it gets worse.

Whenever Transmission is running, I pretty much lose all other network capabilities. My NAS disconnects. My browsing via Firefox on ANY machine (Win or Mac) repeatedly fails to resolve web pages. If I'm downloading any files via the web, they drop to 2k-3K. It's as if Transmission is this giant bandwidth sponge sucking up all available activity from the router. Since this is Uverse, that also means my TV sets start to fail. My VOIP line starts to fail. Everything fails. Transmission becomes this dark god that just hoards everything available, but given the rather anemic download/upload speed it offers, I can't for the life of me figure out what it is doing with that bandwidth! It's not using it to speed up my downloads. But the moment (ok like within 30 seconds really) I shut down Transmission....the entire network returns to normal. I've even done a little test downloading a file I've uploaded to Megaupload previously. It's an 800 meg file. I will start downloading it using a web browser on my Windows box....no issues, it's coming back down to me and completes the download in about 6 mins, give or take...that's a download speed of about 17Mbs/sec....about max of what I can get. But the SECOND I start up Transmission, even if there are no files to download/upload....that download gets clubbed like a baby seal down to around 2K/sec. I exit out of Transmission and immediately start to see speeds pick up on the Windows box again for the download. It may take 3-4 minutes but gradually I'm back up to my full download speed.

I like Transmission, I do. I think I've done everything I'm supposed to...followed the Wiki, followed the hints/tips posted here. But I start the thing and it just kills my network. Is there anything else I can try or should I just bag this one as broken on my system?

Things I've tried (all to no avail):

1) Changed ports on both Transmission and my router - nothing changes
2) Played with just about every possible setting/combination for Global and Speed Limit (turtle) I could conceive. Left upload totally unlimited to see if I was being throttled in some way by the trackers but my ratio is around 1.5 right now so I don't think that's the case. - nothing changes
3) Dropped Peers as low as 50 for Global Maximum and 25 for New. - nothing changes. Oddly enough, I've shot both into the 1000 range just to see if I could force a router fail...same crappy network performance but otherwise, no changes.
4) Unflagged both PEX and DHT, or flagged one and not the other to see if it made a difference. - No changes
5) Unclicked Automatically Map Port. Actually, if I do that, the port dot is red. Unflagging that option (disabling it) turns my dot green. I've tried both ways and other than the dot color...No Changes. Network runs at sub-Acoustic Modem speeds.

I even turned on Transmission while typing this post. I lost this message twice. Turned it off to finish typing it so my browser would function. Fine now.

So do I just write this off as a bad, goofy problem that only impacts me or is there something else I can try?

Thanks for listening to my ramble.

[moldprince]

I've got the same unresolved problem. Same symptoms, I won't go through the litany of similar solutions I've tried.

Definitely not a problem that just affects you.

[Runamuck]

Downloaded and tried the latest nightly....problem persists. This isn't addressed yet.

My only recourse is to switch to another BT client...using Vuze now. Speeds on Vuze now match those of my Windows BT client and I can continue to use my network while it is running. I'll check into the development of Transmission again in a few months and see if the dev team has caught up with their list of bugs. For now, the app is just unusable to me.

[bsonnega]

I hope this gets resolved, I've been having this issue for a few weeks now. Been researching and experimenting, but I've had to switch over to another client for the time being. I'm a long time Transmission user and I'll keep checking back until this is fixed!

[microworx]

HI i just started using transmission since last week when i was running 1.75 it seemed fine but the other day it updated to 1.76 and when i am downloading my internet connection for other devices slows right down
i get dns timeout errors, pages don't load. as soon as i quit transmission it picks up again.

[Fiete5401]

Version 1.76 seems to be much more aggressive than 1.75 in bandwidth usage.
Since running 1.76 it is impossible for me to use any other program that uses my internet connection.

[microworx]

I have noticed that when only seeding the Internet on other devices is normal.

[linenoise]

I am seeing this as well when I fire up more than a couple of torrents. Only happens when downloading. Seems to be more peer count than speed based.

[Nemrod]

In my case version 1.76 is less agressive in than 1.75 but it still using two much bandwith ... shame

[BlueyedBoy]

I'm also having this problem. Trying to download a single torrent, and it effectively blocks me from doing anything else on the Internet. MacBook Pro with 10.6.2. It's a shame, I like the UI on Transmission much more than VUZE, but it's gotta be usable to be, uh, usable. This seems like it should be pretty basic, and it's a problem that's been happening in one form or another for years.

[Nemrod]

Hello,

Except the aggressive use of bandwith, did you noticed slow download rate ?

Thanks

[Superjunior]

I have the same problem. With 1.75 and 1.76 everything else on the network almost stalls, even though Transmission isn't downloading. Unusable as it is now. Going back to 1.74.

[dehjosh]

I have had the same problem for like 10 months now. but its not just computers it slows down. my xbox 360 fails too when i try to get on live.

[Kiskaloo]

I see the same with both Transmission and uTorrent, though uTorrent seems to handle it better (less often). Might try Vuze and see what that does.

Someone on another thread noted it might be a defense by the router to what it considers an "IP flooding" attack? I am using a Linksys WGC200 gateway.

[alembic]

I started using Vuze about a month ago due to this issue and it doesn't bog down my local network.