Difference between revisions of "AMule is slow"

Revision as of 11:23, 20 November 2006

aMule is slow

So aMule is slow? This can be:

• Your fault
• The network's fault

Your fault

General guidelines

This is a list of issues which can be the reason for slow download speeds:

• A low value in "Preferences"->"Download limit".
• A low value in "Preferences"->"Upload limit". Upload limits under 4 kbps limit your download speed to 3 times your upload speed. Upload limits under 10 kbps limit your download speed to 4 times your upload speed. Upload limits above or equal to 10 kbps give you unlimited download speed, limited only by the "Download limit" preference value (read this link to know more about it).
• A too high value in "Preferences"->"Upload limit". Your line may get congested! (depends on your line-speed)
• A too low value in "Preferences"->"Max Connections". There are not enough connections available.
• A too high value in "Preferences"->"Max Connections". Too many connections are congesting your line.
• A too low value in "Core Tweaks"->"Max New Connections". It takes very long to aquire sources.
• A too high value in "Core Tweaks"->"Max New Connections". Your line gets congested, many new connections produce much overhead-bandwidth.
• Having a Low ID.
• Some ISPs block or limit connections to the standard eD2k ports. Try changing the port in "Preferences"->"Connections" to some other values.
• Your firewall may be blocking some ports/protocols used by aMule and/or you did not forward these ports in your router (again, see Low ID).

Congested downlink or uplink cures for ADSL

Many ADSL service providers set up their network so that routers buffer a lot of packets. This can cause severe performance problems; for example a congested uplink can cause a large reduction in downlink speeds too.

The problem is described in the WonderShaper page.

As a rule it is important that on ADSL neither the uplink nor the downlink be used at 100% capacity. Usually 90-95% is a good idea (taking into account overheads too, as a 576KiB/s line cannot actually transfer that much).

Therefore ensure that on 576kb down/288 kib up ADSL line total download speed is at most 52KiB in download and 26KiB in upload.

If aMule is the only significant user of bandwidth, setting its maximum upload and download limits to somewhat lower than that, for example 42KiB/s for download and 21kiB/s for upload, does it.

Otherwise if you have GNU/Linux you can run a traffic shaper that will regulate the total traffic bandwidth. Two ready made shaper scripts are WonderShaper and sabishape.

Another useful but minor improvement is to ensure that there aren't too many upload connections with too small bandwidth. For example with a 21KiB/s upload limit, not more than 7 upload connections, with 3KiB/s each. Probably no more than 5 is a tiny bit better.

The network's fault

We hate to break this to you, but slow speeds aren't always due to bad aMule code or bad configuration. Some factors may include, but not limited to:

• eD2k is a slow network; The eD2k network is one of the largest P2P networks in existance but its primary goal is archive availability. While you do get faster downloads with other popular networks you'll quickly find out that the eD2k network is home to millions of files you'll be unable to find on any other network.
• Credits; If you are running aMule for the first time or if you deleted files in ~/.aMule directory, you'll have no credits. Credits grant faster downloads. If you don't know what they are, read this
• File Availablity; Rare files, old files, extremly new files... these kinds of files have very few sources, so it takes more time for aMule to establish a connection with the few clients sharing it.
• Large queues; eMule, as well as most of its offspring use large queues. aMule defaults to a queue size of 5,000. This ensures that users cannot cut in front of other clients by continuously re-asking the source (an inherent problem in the days before eMule). One must be willing to wait in line and that can, for a new client with no credits, take a long time. You might have to wait 2 weeks before a file is completed if, for example, there is only one source.
• Check the network FAQ.