Optimizing Bittorrent Clients for Speed

NOTE:  This article was originally designed to help achieve the best download speeds in the four clients suggested as Top Picks in my Best Free Bittorrent Client review here at Gizmo's Tech Support Alert.  If you have one of those four bittorrent clients, you should use the new guides as they are more complete and descriptive.

• Optimizing Vuze for Speed (also applies to BitTyrant and older Azureus versions)
• Optimizing µTorrent for Speed (also applies to BitTorrent 6.1)
• Optimizing the Transmission Bittorrent Client for Speed
• Optimizing BitComet for Speed

I have left this guide up as a general guide for those who use other bittorrent clients.  These steps are basic to any bittorrent client.  There are some programs that claim to optimize speed in bittorrent clients.  Those programs should be avoided as they have adware or spyware.  The advice herein has been gathered from my reading of the various information from bittorrent developers and my own experience.  Nothing will get you faster speed than following these basic steps.

Optimizing a bittorrent client for speed is an easy process: Choose a proper port, clear that port through software firewall and router and adjust internal settings based upon upload capacity of the internet connection. 

1,  Choosing a Proper Port:  Azureus-Wiki:  Port is Blacklisted
A single port within the 49152-65534 range should be chosen to avoid ISP blocks and possible conflicts with other applications. 

2.  Forwarding the Port:  Essentially this is about setting permission in your software firewall and router for your bittorrent client to send and receive communications.

Software firewall – The best place to look is in the help file of your software firewall. There are some guides at the µTorrent forum (substitute your client's when necessary) and also at PortForward.com Firewall Guides (choose firewall and then program).  Communications should be allowed for TCP and UDP in both directions.

Router (or modem with firewall) - There are two choices here, Universal Plug n Play (UPnP) or manual forwarding. The choice is basically convenience versus security. UPnP is easy, but has security issues. A router blocks unknown incoming connections at the hardware level and provides significant protection for your computer. Enabling UPnP allows any program to create a port mapping through the router without consent of the owner. I would suggest to at least try manual port forwarding through the router as it is not as difficult as it may seem (especially with the guides) and is safer. In any event, read the following section on UPnP as it is an either/or situation and UPnP will have to be disabled if manually forwarding. 

UPnP (NAT-PMP - Apple)  Must be enabled/disabled in client and router

Manual Port Forwarding:  Portforward.com Router Index

Again, the router documentation is the best place to look for this information. PortForward.com Router Index has guides for almost all routers and bittorrent programs. Choose the make and model of your router and then your bittorrent program and you will be taken to a page with a guide specific to your client and router.  Many of the bittorrent client screenshots will be out of date as the clients are constantly updated, but the information should still apply.  Make certain to also check the Static IP Guide.

When finished, you can test to see if your port is properly forwarded at Can you see me?.

3.  Adjusting Internal Settings:  This involves taking a speed test, using the calculator to determine the settings that should be used and inputing those settings in your client.  The most important setting is to cap upload at no more than 80% of your overall upload capacity as there needs to be room for communications to the tracker or else download speeds will suffer.  Download could also be capped (at 90%), but this is not necessary as this is rarely an issue.

Speed Test: Speedtest.net
First the upload capacity of your internet connection must be determined by taking an online speed test. You should stop all internet activity, including torrents, before taking the test and the test should be taken a few times to obtain a reliable average. Speedtest.net has test locations worldwide and will highlight the one closest to you. Note that the result of Speedtest.net is in kilobits (kb) and bittorrent clients show speeds in kilobytes (kB). This is important as 8kb = 1kB. See Azureus-Wiki: Data Units

Calculator:  Azureus Upload Settings Calculator
Once you have an average upload speed for your connection go to the online Azureus Upload Settings Calculator. Although designed for Azureus, this calculator will work for all bittorrent clients. Enter your average upload speed in the appropriate box and the calculator will automatically give the proper figures to adjust various options in your client.

The above settings should work well most of the time.  Downloads of individual torrents depends on other factors.  See Good Torrents

Related Articles:

• What is Bittorrent?
• Best Free Bittorrent Client
• Searching for Torrents (Popular Torrent Search Sites)
• Finding Legal (and Free) Torrents