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Azureus vs. µTorrent: The Showdown
September 2, 2006
Thomas Mennecke
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Throughout P2P history, several rival file-sharing clients have caused a sharp divide in an otherwise united community. BearShare had Shareaza, while Kazaa had Morpheus. Although most of these clients are now defunct, the conditions that cause internal conflict are not. As the file-sharing community shifts towards BitTorrent, two of the most popular clients, Azureus and µTorrent, continue the competitive nature that helps drive P2P to the success it’s achieved today.


Azureus was released on SourceForge in June of 2003. As one of the first BitTorrent clients, it quickly gained a large following – providing you had the processing resources. Azureus was quickly known as a resource hog, consuming large quantities of memory and CPU power. This resource consumption is largely due to the client’s reliance on the Java platform.

But this didn’t matter to those on higher performance machines. Besides, this type of concern was for those on a Pentium III or lacking sufficient memory. For the rest of the Azureus community, this BitTorrent client represented the cutting edge of file-sharing technology. In fact, Azureus wasn’t just another BitTorrent client in a sea of file-sharing plankton; it’s open source and was the first application to introduce DHT (Distributed Hash Table) technology.

µTorrent is a relative newcomer to the file-sharing world. Released in October of 2005, µTorrent was seen as an alternative to Azureus. Lightweight in comparison, µTorrent consumed only about 4 kilobytes of memory – an astonishing feat considering its functionality.

Adding to µTorrent’s impressive nature was the size of the application. It didn’t require an installer, and could be downloaded and launched as an executable at under 100 kilobytes. For those who had lower performance machines and didn’t wish to yield computer performance, yet still craved their BitTorrent fun, µTorrent was the application of choice.

To remain competitive, µTorrent later added Mainline DHT support. Aside from a few minor bells and whistles, µTorrent’s functionality equaled any BitTorrent client. Despite these impressive advantages, µTorrent still lacked one major attribute – an open source code.

The difference between µTorrent and Azureus serves as a microcosm into the P2P community – open source vs. closed source, bloatware vs. smallware, the haves vs. have nots.

Downloading the Client

The first thing we need to do is download the respective BitTorrent applications. µTorrent is available at, while Azureus is available at its SourceForce location and its commercial site,

The difference between the two applications is immediately apparent. µTorrent is available with or without an installer, and for the purposes of this article we simply downloaded the executable. Despite the added functionality to the client, µTorrent is still only 171 Kilobytes. Conversely, Azureus is a whopping 8.6 Megabytes, not including the Java install.

However, for most people who plan to use these applications, bandwidth is likely not a concern. If you’re going to use BitTorrent, chances are the multimedia sought after will be considerably larger than 8.6 Megabytes.

The Download

For the purposes of this article, Slyck downloaded Revsion3’s “Ctrl+Alt+Chicken”, episode 7. is technology information website that frequently releases various Creative Commons tech TV shows. “Ctrl+Alt+Chicken” is a slight departure from their format, and features tech geeks trying to cook with limited skills.

The file is 146 megabytes, and is in the MOV file format.

With µTorrent, we clicked and dragged the torrent file into the client. Within seconds, the file began discovering peers and was downloading at over 850 kilobytes per second. The µTorrent client consumed no more than 6,000 kilobytes of memory, out of a possible 1 gigabyte. The average memory consumption averaged around 1,000-3,000 kilobytes of memory. Total CPU usage averaged between 4% and 9%. Within 4 minutes, the file downloaded and Slyck was enjoying episode 7.

Like µTorrent, Azureus had no problems finding peers and was downloading at top speed (although like µTorrent, available bandwidth wasn’t maxed.) Unlike µTorrent however, Azureus uses a considerable amount of memory resources. Azureus used between a staggering 50,000-53,000 kilobytes of memory, however there wasn’t a dramatic increase in CPU usage (between 5% and 11%.) The file was downloaded within the same approximate time as µTorrent.


Both Azureus and µTorrent support the nine essential core features that most BitTorrent users will utilize. In other words, for the average BitTorrent user, both clients have the necessary features to get the job done, and do a terrific job in doing it.

There are some differences of course between the two. Azurues is a cross platform client, while µTorrent only works on Windows. In addition, Azureus’ DHT supports NAT transversals, whereas µTorrent’s mainline DHT is not capable of doing so.

Azureus is a feature rich application. With its open source nature, hundreds of plug-ins are available to build upon this client. The question of which client is “better” ends up being a personal choice. Some people like small Honda Civics for their low emissions and simplicity. Others want an eight cylinder Camaro for its upgradeability and power.

If computer resource allocation is a priority, µTorrent is likely the right choice. If these is not a concern and the user wants to let the horses fly, Azurues is like a 68 Camaro shell just waiting to be modified. In either case, both clients get the job done, and is a reflection of the hard work, talent and dedication from both development teams.

This story is filed in these Slyck News categories
BitTorrent :: BitTorrent Clients
File-Sharing/P2P Related :: Statistics/Analysis

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