The most significant improvement or new feature of Dragon NaturallySpeaking version 3.0 is the improved accuracy. To get better accuracy, Dragon Systems has made a number of changes to the speech recognition system and data files.

Here is a brief list of some of the changes which were made in version 3.0 which contribute to the improved accuracy.

Dragon NaturallySpeaking version 3.0 has new acoustic models which do a better job of matching a wider variety of speech to phonemes and words. These new acoustic models are larger than the acoustic models which were used in Dragon NaturallySpeaking version 2.0.

1. Dragon NaturallySpeaking version 3.0 has new vocabulary files which do a better job at predicting word usage. The new vocabulary files in the Standard Edition and the Preferred Edition both have more words and more statistical information. These new BestMatch vocabulary files actually have over 45,000 words instead of the standard 30,000 words. In the Professional Edition of Dragon NaturallySpeaking version 3.0, you also have the choice of using an even larger vocabulary file which has over 64,000 words. The 64,000 word vocabulary also has even more statistical information relative to the number of words than 45,000 word vocabulary included in the Standard Edition and the Preferred Edition.
   
2. The vocabulary files in Dragon NaturallySpeaking version 3.0 now contain a significant number of trigrams. Trigrams are the name of statistical data that models the probability of words in sets of three. The addition of trigrams makes Dragon NaturallySpeaking much more accurate in the presence of homonyms.
   
3. In Dragon NaturallySpeaking version 3.0, the command versus dictation discrimination logic has been completely rewritten. This means that Dragon NaturallySpeaking version 3.0 is much less likely to mistake a command for dictation or vice versa. (However, it also means that if you speak a command which does not exactly match the grammar, it is more likely to be typed.)
   
4. Also in Dragon NaturallySpeaking version 3.0, the selection logic was reworked to be faster and more accurate. This is the logic which allows you to say "Select <text>" or "Correct <text>".
   
5. Dragon NaturallySpeaking version 3.0 also has the capability of using significantly more processing power to increase the accuracy further. This is optional, but if you have a very fast processor, you can change the trade-off between speed and accuracy to take advantage of your additional resources.
   
6. Finally, Dragon NaturallySpeaking version 3.0 includes some other algorithmic improvements which have small but measurable impact on the accuracy.

In summary, BestMatch is the name of the improvements in Dragon NaturallySpeaking version 3.0 which improve your accuracy. Dragon Systems internal tests indicate that when using the larger acoustic models and larger vocabularies along with the other improvements in version 3.0, users experience approximately 25 percent fewer errors. However, the experience of heavy users is more pronounced. Everybody that uses Dragon NaturallySpeaking version 3.0 with BestMatch technology notices a significant improvement in the accuracy.

On the other hand, there is a downside to the BestMatch technology. Using the larger acoustic files and larger vocabulary files requires both more RAM and more processor. When using these improvements, you will need at least a Pentium 200 MHz processor and 64 MB of RAM instead of a 133 MHz processor and 32 MB of RAM.