Ques re advantages of bitlocker & TPM?

[pae77]

Well I've got W7 ultimate (the RC) as my main OS now and I see it has Bit locker encryption that can work with the T61p's TPM. Can anyone briefly explain in very simple terms what the security advantages of enabling Bit locker whole drive encryption with the TPM are and what the downsides are, if any?

For example, does it cause the system to run and or boot noticeably slower?

How does this protect my data beyond the Hard Drive and power on passwords I'm already using? I mean, what does it protect me from?

Are there any risks to turning this on and enabling it?

Is it a good idea to use it or not?

Thanks in advance for any comments on this.

[dsvochak]

Excellent questions. Makes two of us who'd like some expert opinions.

[R-T-B]

I believe (don't quote me on this) that bitlocker pretty much encrypts the drive in software, whereas the IBM drive password does it in hardware. I don't know which one is stronger, obviously having both is the most secure but I do know bitlocker slows system performance and boot time wheras the IBM drive password does nothing of the sort due to it's hardware nature.