Optimizing BitComet for Speed

Introduction

This guide shows how to speed up downloads in BitComet.  All bittorrent programs need to have their incoming and outgoing communications flow freely in order to achieve the highest download speeds and that is essentially what this guide is about.

This guide was put together using information given by the developers of bittorrent programs at their forums, guides and FAQs.  There are no secret tricks, just the real basics of proper set up of a bittorrent program.  Following these simple steps should result in increased download speed.

These are the basic principles of optimizing a bittorrent client, like BitComet, for speed: 

• Choose a proper port to avoid ISP blocks and conflicts with other programs
• Forward that port through any software firewall and router to allow incoming connections
• Adjust internal settings based upon upload capacity of the internet connection to allow room for outgoing communications and to distribute upload efficiently. 

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

To avoid messing up a network connection that is already cleared, first check and see if your communications are blocked or are already clear.

Click to Test Your Port  Success-just go to Adjusting Internal Settings.   Error- follow all steps.

Port number in BitComet is at Tools>Options>Connection.

If you failed the port test above, then you should first set your port to a proper one.  The most important choice here is to avoid using a port within the 6881-6999 range.  This was the range originally used by bittorrent programs and is often blocked by Internet Service Providers (ISPs).  (If your port was in this range, change and re-test). The safest choice is a port in the 49152-65534 range as this will avoid ISP blocks and possible conflicts with other applications.
Azureus-Wiki:  Port is Blacklisted

Forwarding The Port

Introduction
A router will block incoming communications unless an exception is made.  All software firewalls will block incoming communications and most will also block outgoing communications, unless an exception is made.  If you are "firewalled", then other people will not be able to initiate connections with you (see Why Is Being Firewalled Bad).
As there are many firewalls and routers, this guide can not give explanations as to each.  However, there are guides available, on the internet for most firewalls and routers and this guide will link you to them.

Software Firewall - The permission should be set to allow TCP and UDP in both directions. Generally, you will have a choice to set permission for  the µTorrent port or for the µTorrent program.  Setting permission for the port is the safer choice.  You can check these options for guides:

• The help file of your software firewall is the best place to look
•  The µTorrent forum  has some guides posted
•  PortForward.com Firewall Guides(choose firewall and then program) also has some guides.

Router - There are two choices here.  The easier way is to use UPnP.  However, this has a possible security issue.  Using UPnP allows any program to create a port mapping through the router without consent of the owner.  The other choice is to manually forward the port through the router.  This does not have that security issue, but involves going through several steps to accomplish.  Using the guides linked herein, this should not be that difficult and is the preferred method.

UPnP - The Easy Way -  Enable UPnP  in BitComet and router.

In BitComet  at Tools>Options>Connection

Manual Forwarding-The Preferred Way

1. UPnP must be disabled in BitComet (see Image above). 
2. Use the Static IP Guide.
3. Set permission for BitComet port.  This should be set to allow both TCP and UDP communications.
   You can check these options for guides: 
   

• The help file of your router is the best place to look
• Portforward.com BitComet Router Index  has guides for most routers

Click Here to Re-Test Port    Success-Proceed to next step.   Error- re-do steps or seek help in Forums.

Adjusting Internal Settings

Introduction
The  most important setting here is to cap upload in BitComet to 80% of your overall upload capacity.   Setting upload in BitComet is a fine line.  The more upload you give, the more download you will get from other peers. However, if upload is set too high, or to unlimited, then download speeds will suffer as outgoing communications (acknowledgment signals, resend requests etc) will be interfered with. Other adjustments are made here to distribute your upload so that you receive back the most download from other peers.

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
Note:  Before taking the speed test, press Settings in the upper left of the speedtest.net page and make certain the Speed Measurement is set to either kilobits or kilobytes.  This will help in inputing into the caculator below.

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.

Input Results Into BitComet - Screen shots of locations in BitComet of settings to be adjusted

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

Media Preview  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

Good Torrents

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

Related Articles

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.

To those who post thanks.  I always appreciate hearing from those who this helped and I do read the posts regularly.  I used to respond to each thanks, but realized it was clogging up the comments section.  I thank all those who have posted their appreciation and all those who will.