is BitLocker an important tool for notebooks? Will it slow it down?

I wanted to clean install and upgrade to vista ultimate but later had decided to stay with my home premium until somewhere I read vista ultimate's bitlocker is very important feature for notebook, so its worth it to upgrade. Now I know encryption means only my user account can access the files, but wouldn't it make the transfer, writing, reading of files slower?? Also, how much is Bitlocker important in day to day activity and in general is ultimate really worth to upgrade. I am just a student, and need media more than office productivity tools.
Thanks for help.

 

Bitlocker requires a user authenticated password upon booting up the computer, so its not like your computer has to encrypt/decrypt files on the fly as it reads/writes. The performance hit from this technology is said to be less than 10%.

More on Bitlocker here:
http://www.winsupersite.com/showcase/winvista_bitlocker.asp

Really detailed delving into Bitlocker here:
http://technet.microsoft.com/en-us/library/cc766200.aspx

 

I forgot to answer these questions. Bitlocker brings quite a bit of complications; of course if you lose your password, the data is lost without a doubt. Also, battery life may suffer as the system is under heavier load. Lastly, according to my first link, setting up Bitlocker requires two partitions for the boot files and operating system. Its a bit complicated and a bit of an "overkill" security feature for a student (unless you have critical data).

 

Uh... yes it does. That's exactly what it does. That technet article you linked to explains it:

 

OK... but I was explaining how Bitlocker doesn't bog down the system much because of its authentication method... I don't need to explain what Bitlocker does to the OP since he obviously knows what it does, I wanted to explain how it does what it does without taking a major performance hit.

 

It's hard drive encryption. It doesn't 'just' put a password at start up. It encrypts all data on disc with AES algorithm. Password is only to unlock the key that decrypts data on the fly.