Optimizing BitComet for Speed

Optimizing a Bittorrent client like BitComet 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.  Basically, the port forwarding allows incoming communications and the capping of upload allows room for outgoing communications.  This guide hopes to set forth clearly these basic "truths" for getting the best download speeds in Bitcomet. 
There are some programs that claim to optimize speed in BitComet.  Such programs are a scam and generally contain adware or spyware.  I have seen it said, by the developers of all bittorrent programs, that nothing will increase your download speed in a bittorrent client more than the basic steps set forth herein. 

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.
The setting for this in BitComet is at Tools>Options>Connection.

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

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  Must be enabled/disabled in client and router.  In BitComet  at Tools>Options>Connection

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  Many of the µTorrent client screenshots will be out of date as it is constantly updated, but the information should still apply and the screenshots here should help.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

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.
µTorrent does have a built in Speed Guide (Ctrl+G), which has links to a speed test, port test and has a pulldown menu of common upload speeds that will automatically make these adjustments.  I ran my µTorrent under both configurations and found my speed significantly better using the below.  There is very little extra work involved and the results make it worth it.

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.

BitComet Settings

Upload and Download Limits Tools>Options(Ctrl+P)>Connection

Connections per Torrent and Globally Tools>Options(Ctrl+P)>Advanced

Max Simultaneous Downloads Tools>Options(Ctrl+P)>Task

Also at Tools>Options(Ctrl+P)>Task is the setting for Bitcomet's "Media Preview" option.  This allows preview of audio or video media, which can help stop the waste of bandwidth on fake or poor quality content.  However, this will also slow download speed.  On my installation this was enabled by default and should be disabled for best download speed.  Fake and poor quality torrents can be avoided by reading comments and ratings at torrent search sites.

Tools>Options(Ctrl+P)>Task

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

If you have any questions or suggestions, you may use the comments below.  But it would be better to post in our Bittorrent Client forums.

After you have set up your BitComet, you might want to check my articles

• Searching for Torrents (Popular Torrent Search Sites) for a listing of the most popular torrent search sites and their features.
• Finding Legal (and Free) Torrents which lists, with comments, sites that offer only legally downloadable and distributable content.

If you have any questions or suggestions, please post in the comments below.  If you need help, then our forums would be a better place to post.

This guide was updated on November 20, 2008, to reflect a change in menu name in BitComet.