Maximize Bittorrent P2P Download Speed

by David Hakala

Bittorrent P2P (peer-to-peer) networks are delightful when downloads are fast. They are especially irritating when they are slower than direct-connection downloading. These tips can help you squeeze the most speed out of your Bittorrent sessions.

Optimize your maximum number of half-open TCP connections. Those are the connections you make to different peers on a P2P network. In Windows XP SP2 and SP3, the maximum number of connections is set at 10 by default. This arbitrary ceiling limits your exposure to potential virus sources, but it slows down your downloading. Better to have 50 peers each dishing parts of a file at 10 Kbps than just 10.

A tiny application with the unlikely name of EvID4226Patch.exe (ZIP archive file, 40 KB) lets you set any number of maximum half-open TCP connections in the Windows XP environment. Try something in the range of 50 to 100; more is not better.

Then you must configure your Bittorrent client to use that new maximum number of connections. The procedure varies from client to client. In the popular uTorrent client, select Options, Preferences, Advanced options, max half-open TCP.

Some Windows Update installations and system optimizing applications, like Advanced System Care, “correct” your maximum number of half-open TCP connections back to 10. So it is a good idea to run EVID4226Patch.exe after every update of system optimization, and to check its status occasionally.

Next is Torrent client configuration. To apply these tweaks you need to know your maximum download speed. You can choose a speed-testing server from a worldwide list here at DSL Reports or refer to the Tiplet article about Broadband connection speed.

The settings you need to tweak will be found in most Bittorrent clients’ options, settings, or preferences menus.

1. Cap your maximum upload speed at 80 percent of your tested maximum upload speed, leaving more bandwidth for downloading.

2. Set your maximum download speed at 95 percent of your tested maximum download speed, leaving you a bit of bandwidth for browsing and checking mail while downloading P2P files.

3. Set “maximum connected peers per torrent” to 1.5 times the maximum upload speed you set in step 1. For example, if you capped upload speed at 50 KBps then set max peers at 1.5 x 50 = 75.

4. Set “maximum upload slots” to 1 + (upload speed / 6). So if the maximum upload speed you set in step 1 is 50 KBps, set the maximum number of upload slots at 1 + (50 / 6) = 9. Round decimals down.

There are some other “tweaks” to try. These miscellaneous tips will help you maximize download speeds:

When choosing a torrent to download, choose the one with the highest seeds/peers ratio. Fifty seeds to 50 peers are better than 500 seeds to 1,000 peers.

Change the default port to anything outside of Bittorrent’s standard 6881-6999 range. ISPs like to throttle traffic in that range.

Disable Windows Firewall, which often hinders P2P traffic. Instead, use a more configurable firewall program such as ZoneAlarm.

Turn on encryption so ISPs can’t tell you are sending and receiving P2P traffic, which they like to throttle.

Optimize your Internet connection with the free TCP Optimizer program. Move the slidebar to your maximum download rate in Kilo-bits per second (8 times kilo-Bytes per second).

David Hakala has perpetrated technology tutorials since 1988 in addition to committing tech journalism, documentation, Web sites, marketing collateral, and profitable prose in general. His complete rap sheet can be seen at http://www.linkedin.com/in/dhakala