I've read about the performance hit when encrypting your hard drive with Bitlocker, and since I'm using my computer to play games once in a while, I'm a little hesitant.

I have two partitions on the disk though, so my question is: if I only enable Bitlocker on the secondary partition and keep the data that needs encryption there, will there still be a decrease in performance on the system partition where Windows and my games are installed?

I'm thinking yes, since they're on the same physical disk, but I'm no expert, hence the question.


I guess what you need to evaluate is why you need to encrypt the machine.

The reason may as well help us to determine what's best for you. Encryption these days, especially when you are talking about whole disk encryption, is basically only useful to prevent one attack - which is, somebody getting your machine while it was powered off, and you want to prevent them from getting the data inside.

For most other purpose, you better invest in

(1) network access control, which includes, but not limited to, wireless security and use of encrypted protocol (e.g. ssh as opposed to telnet, https as opposed to http), use of VPN when in public networks (2) file-based, or container-based security, that is, something like truecrypt -- this is the case when you do have something to hide (illegal, secret or otherwise), and because this is not whole disk encryption you won't have to mount it all the time. (3) physical security - it's old saying that physical access equals root. while this may not be as true nowadays, there is still some weight.

For your question - - whether it will decrease performance if the drives are logically separated - Not usually. Bitlocker volume are only encrypted/decrypted when there is access, and encrypting nowadays is a very simple matter, and won't tax your CPU much unless your secrets are big, big streams of video or images for that matter - read/writes will not tax the harddrive more than 1.1x (with overheads) it is when it was not encrypted. CPU load is negligible these days if R/W is not significant on data drive during gaming.

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  • Sorry for not responding sooner, and thanks for your informative reply. The reason for the encryption is that I use the computer in question for both work and play, and the work files are sensitive since they contain ftp and database passwords etc. I want to encrypt my work files in case the laptop gets stolen or lost. – Skumberg Feb 8 '11 at 1:13

Why not utilize a hard drive utilizing SED technology where the encryption takes place in hardware as opposed to software. There's NO performance hit at all in that case as the encryption chip encrypts faster than the physical read/write process.

Seagate and other vendors offer these drives for much cheaper than the cost of CPU or memory upgrades (to gain back lost CPU cycles from s/w encryption)

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  • Thanks for the reply! It's a laptop, and I really don't want to bother switching out the hard drive in it for the moment, but I will keep your suggestion in mind when I build my next stationary computer. – Skumberg Feb 8 '11 at 1:16

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