With my T7300 2.0GHz and Kingston V100 64gb SSD the results are
Bitlocker off → on
Sequential read 243 MB/s → 140 MB/s
Sequential write 74.5 MB/s → 51 MB/s
Random read 176 MB/s → 100 MB/s
Random write, and the 4KB speeds are almost identical.
Clearly the processor is the bottleneck in this case. In real life usage however boot time is about the same, cold launch of Opera 11.5 with 79 tabs remained the same 4 seconds all tabs loaded from cache.
A small build in VS2010 took 2 seconds in both situations. Larger build took 2 seconds vs 5 from before. These are ballpark because I'm looking at my watch hand.
I guess it all depends on the combination of processor, ram, and ssd vs hdd. In my case the processor has no hardware AES so compilation is worst case scenario, needing cycles for both assembly and crypto.
A newer system with Sandy Bridge would probably make better use of a Bitlocker enabled SDD in a development environment.
Personally I'm keeping Bitlocker enabled despite the performance hit because I travel often. It took less than an hour to toggle Bitlocker on/off so maybe you could just turn it on when you are traveling then disable it afterwards.
This test is using a system partition. Results for a non-system partition are a bit better.
Score decrease: Read: 5% Write: 16%
Without BitLocker:
With BitLocker:
So you can see that with a very strong configuration and a modern SSD disk you can see a small performance degradation with tests. I don't know what about a typical work, especially with the Visual Studio.
Having used a laptop with BitLocker enabled for almost 2 years now with more or less similar specs (although without the SSD unfortunately), I can say that it really isn't that bad, or even noticable. Although I have not used this particular machine without BitLocker enabled, it really does not feel sluggish at all when compared to my desktop machine (dual core, 16 GB, dual Raptor disks, no BitLocker). Building large projects might take a bit longer, but not enough to notice.
To back this up with more non-scientifical "proof": many of my co-workers used their machines intensively without BitLocker before I joined the company (it became mandatory to use it around the time I joined, even though I am pretty sure the two events are totally unrelated), and they have not experienced noticable performance degradation either.
For me personally, having an "always on" solution like BitLocker beats manual steps for encryption, hands-down. Bitlocker-to-go (new on Windows 7) for USB devices on the other hand is simply too annoying to work with, since you cannot easily exchange information with non-W7 machines. Therefore I use TrueCrypt for removable media.
I am talking here from a theoretical point of view; I have not tried BitLocker.
BitLocker uses AES encryption with a 128-bit key. On a Core2 machine, clocked at 2.53 GHz, encryption speed should be about 110 MB/s, using one core. The two cores could process about 220 MB/s, assuming perfect data transfer and core synchronization with no overhead, and that nothing requires the CPU in the same time (that one hell of an assumption, actually). The X25-M G2 is announced at 250 MB/s read bandwidth (that's what the specs say), so, in "ideal" conditions, BitLocker necessarily involves a bit of a slowdown.
However read bandwidth is not that important. It matters when you copy huge files, which is not something that you do very often. In everyday work, access time is much more important: as a developer, you create, write, read and delete many files, but they are all small (most of them are much smaller than one megabyte). This is what makes SSD "snappy". Encryption does not impact access time. So my guess is that any performance degradation will be negligible(*).
(*) Here I assume that Microsoft's developers did their job properly.
The difference is substantial for many applications. If you are currently constrained by storage throughput, particularly when reading data, BitLocker will slow you down.
It would be useful to compare with other software based whole disk or whole partition encryption like TrueCrypt (which has the advantage if you dual boot with Linux since it works for both Windows and Linux).
A much better option is to use hardware encryption, which is available in many SSDs as well as in Hitachi 7200 RPM HDD. The performance of encrypted v. not is undetectable, and the encryption is invisible to operating systems. If you have a decent laptop, you can use the built-in security functions to generate and store the key, which your password unlocks from the encrypted key storage of the laptop.
I used to use the PGP disk encryption product on a laptop (and ran NTFS compressed on top of that!). It didn't seem to have much effect if the amount of disk to be read was small; and most software sources aren't huge by disk standards.
You have lots of RAM and pretty fast processors. I spent most of my time thinking, typing or debugging.
Bitlocker to Go（Bitlocker 应用于拇指驱动器的加密）在读/写时间方面确实会减慢很多速度。只要您记住拇指驱动器上的密码，并且愿意等待它格式化/初始化驱动器，使用它并不太难，但根据我的经验，它使访问闪存驱动器的速度慢了大约 4 倍。不知道为什么它会减慢拇指驱动器而不是磁盘的速度，但这对我和我的同事来说就是这样。
基于我在工作中使用 Bitlocker 取得的成功，我为我的家用计算机购买了 Windows Pro 以获得 Bitlocker，并计划用它加密一些目录，例如财务等。
My current work machine came with bitlocker, and being an upgrade from the prior model. It only seemed faster to me. What I have found, however, is that bitlocker is more bullet proof than truecrypt, when it comes to accurately laying down the data. I do a lot of work in SAS which constantly writes backup copies to disk as it moves along and shoots a variety of output types to disk at the end. SAS works fine writing output from multithreaded processes back to bitlocker and doesn't seem to know it's there. This has not been the case for me with truecrypt. I'm not sure what happens or how, but I found that processes got out of synch when working with source/output data in a truecrypt container, which is what I installed on my second work computer since it had no bitlocker. The constant backups were shooting to an SSD while the truecrypt results were on a regular HD. Maybe that speed difference helped trip it up. Whatever the cause, I had to quit using truecrypt on that second computer because it made my SAS results out of synch with respect to processing order and it screwed up some of my processes and data. Scary stuff in my world.
I work with people who have successfully used Truecrypt on the exact same computer, but they weren't using a disk intensive app. like SAS.
Bitlocker to Go, the encryption which bitlocker applies to thumb-drives, does slow things down quite a bit when it comes to read/write times. It's not too hard to use as long as you remember your password on the thumbdrive, and are willing to wait for it to format/initialize the drive, but in my experience it made access to the flash drive about 4 times as slow. Don't know why it would slow down a thumb drive and not a disk but that's how it was for me and my coworker.
Based on my success with bitlocker at work, I bought Windows Pro for my home computer to get bitlocker and plan to encrypt some directories with it for things like financials.
发布评论
评论（7）
使用我的 T7300 2.0GHz 和 Kingston V100 64gb SSD，结果是
显然，处理器是这种情况下的瓶颈。但在实际使用中，启动时间大致相同，具有 79 个选项卡的 Opera 11.5 冷启动保持相同的 4 秒，所有选项卡均从缓存加载。
VS2010 中的小型构建在这两种情况下都花费了 2 秒。较大的构建需要 2 秒，而之前需要 5 秒。这些都是大概的，因为我正在看着我的表针。
我想这完全取决于处理器、内存、SSD 与 HDD 的组合。就我而言，处理器没有硬件 AES，因此编译是最坏的情况，需要汇编和加密周期。
采用 Sandy Bridge 的较新系统可能会在开发环境中更好地利用支持 Bitlocker 的 SDD。
就我个人而言，尽管性能受到影响，但由于我经常出差，我仍保持启用 Bitlocker。打开/关闭 Bitlocker 只花了不到一个小时，因此也许您可以在旅行时将其打开，然后再将其禁用。
Thinkpad X61、Windows 7 SP1
With my T7300 2.0GHz and Kingston V100 64gb SSD the results are
Clearly the processor is the bottleneck in this case. In real life usage however boot time is about the same, cold launch of Opera 11.5 with 79 tabs remained the same 4 seconds all tabs loaded from cache.
A small build in VS2010 took 2 seconds in both situations. Larger build took 2 seconds vs 5 from before. These are ballpark because I'm looking at my watch hand.
I guess it all depends on the combination of processor, ram, and ssd vs hdd. In my case the processor has no hardware AES so compilation is worst case scenario, needing cycles for both assembly and crypto.
A newer system with Sandy Bridge would probably make better use of a Bitlocker enabled SDD in a development environment.
Personally I'm keeping Bitlocker enabled despite the performance hit because I travel often. It took less than an hour to toggle Bitlocker on/off so maybe you could just turn it on when you are traveling then disable it afterwards.
Thinkpad X61, Windows 7 SP1
一些实际测试...
此测试使用系统分区。非系统分区的结果要好一些。
分数减少：
阅读：5%
写入：16%
不使用 BitLocker：
使用 BitLocker：
因此，您可以看到，通过非常强大的配置和现代 SSD 磁盘，您可以通过测试看到性能略有下降。我不知道典型的工作怎么样，尤其是使用 Visual Studio。
Some practical tests...
This test is using a system partition. Results for a non-system partition are a bit better.
Score decrease:
Read: 5%
Write: 16%
Without BitLocker:
With BitLocker:
So you can see that with a very strong configuration and a modern SSD disk you can see a small performance degradation with tests. I don't know what about a typical work, especially with the Visual Studio.
使用启用 BitLocker 的笔记本电脑已经快两年了，规格或多或少相似（尽管不幸的是没有 SSD），我可以说它确实没有那么糟糕，甚至没有那么明显。虽然我没有在没有启用 BitLocker 的情况下使用过这台特定的机器，但与我的台式机（双核、16 GB、双 Raptor 磁盘、无 BitLocker）相比，它确实一点也不迟缓。构建大型项目可能需要更长的时间，但还不足以引起人们的注意。
用更多非科学的“证据”来支持这一点：在我加入公司之前，我的许多同事在没有 BitLocker 的情况下大量使用他们的机器（在我加入公司的时候就强制使用它，尽管我很确定两个事件完全无关），并且它们也没有经历明显的性能下降。
就我个人而言，拥有像 BitLocker 这样的“始终在线”解决方案胜过手动加密步骤，毫无疑问。另一方面，用于 USB 设备的 Bitlocker-to-go（Windows 7 上的新功能）实在太烦人了，因为您无法轻松地与非 W7 计算机交换信息。因此我使用 TrueCrypt 作为可移动媒体。
Having used a laptop with BitLocker enabled for almost 2 years now with more or less similar specs (although without the SSD unfortunately), I can say that it really isn't that bad, or even noticable. Although I have not used this particular machine without BitLocker enabled, it really does not feel sluggish at all when compared to my desktop machine (dual core, 16 GB, dual Raptor disks, no BitLocker). Building large projects might take a bit longer, but not enough to notice.
To back this up with more non-scientifical "proof": many of my co-workers used their machines intensively without BitLocker before I joined the company (it became mandatory to use it around the time I joined, even though I am pretty sure the two events are totally unrelated), and they have not experienced noticable performance degradation either.
For me personally, having an "always on" solution like BitLocker beats manual steps for encryption, hands-down. Bitlocker-to-go (new on Windows 7) for USB devices on the other hand is simply too annoying to work with, since you cannot easily exchange information with non-W7 machines. Therefore I use TrueCrypt for removable media.
我这里是从理论的角度来说的；我还没有尝试过 BitLocker。
BitLocker 使用带有 128 位密钥的 AES 加密。在主频为 2.53 GHz 的 Core2 机器上，使用一个核心的加密速度应约为 110 MB/s。假设完美的数据传输和核心同步且没有任何开销，并且没有任何事情需要同时使用 CPU（实际上这是一个糟糕的假设），两个核心的处理速度约为 220 MB/s。 X25-M G2 宣布的读取带宽为 250 MB/s（这就是规格所说的），因此，在“理想”条件下，BitLocker 必然会出现一点速度减慢。
但是读取带宽并不那么重要。当您复制大文件时，这一点很重要，而这并不是您经常做的事情。在日常工作中，访问时间更为重要：作为开发人员，您创建、写入、读取和删除许多文件，但它们都很小（其中大多数都小于 1 MB）。这就是 SSD 变得“敏捷”的原因。加密不会影响访问时间。所以我的猜测是任何性能下降都可以忽略不计（*）。
(*) 在这里，我假设 Microsoft 的开发人员正确地完成了他们的工作。
I am talking here from a theoretical point of view; I have not tried BitLocker.
BitLocker uses AES encryption with a 128-bit key. On a Core2 machine, clocked at 2.53 GHz, encryption speed should be about 110 MB/s, using one core. The two cores could process about 220 MB/s, assuming perfect data transfer and core synchronization with no overhead, and that nothing requires the CPU in the same time (that one hell of an assumption, actually). The X25-M G2 is announced at 250 MB/s read bandwidth (that's what the specs say), so, in "ideal" conditions, BitLocker necessarily involves a bit of a slowdown.
However read bandwidth is not that important. It matters when you copy huge files, which is not something that you do very often. In everyday work, access time is much more important: as a developer, you create, write, read and delete many files, but they are all small (most of them are much smaller than one megabyte). This is what makes SSD "snappy". Encryption does not impact access time. So my guess is that any performance degradation will be negligible(*).
(*) Here I assume that Microsoft's developers did their job properly.
对于许多应用来说，差异是巨大的。如果您当前受到存储吞吐量的限制，特别是在读取数据时，BitLocker 会减慢您的速度。
与其他基于整个磁盘或整个分区加密的软件（如 TrueCrypt）进行比较会很有用（如果您与 Linux 双重启动，则它具有优势，因为它适用于 Windows 和 Linux）。
更好的选择是使用硬件加密，许多 SSD 以及 Hitachi 7200 RPM HDD 都提供该功能。加密v.不加密的性能是不可检测的，并且加密对于操作系统来说是不可见的。如果您有一台不错的笔记本电脑，您可以使用内置的安全功能来生成和存储密钥，您的密码可以从笔记本电脑的加密密钥存储中解锁该密钥。
The difference is substantial for many applications. If you are currently constrained by storage throughput, particularly when reading data, BitLocker will slow you down.
It would be useful to compare with other software based whole disk or whole partition encryption like TrueCrypt (which has the advantage if you dual boot with Linux since it works for both Windows and Linux).
A much better option is to use hardware encryption, which is available in many SSDs as well as in Hitachi 7200 RPM HDD. The performance of encrypted v. not is undetectable, and the encryption is invisible to operating systems. If you have a decent laptop, you can use the built-in security functions to generate and store the key, which your password unlocks from the encrypted key storage of the laptop.
我曾经在笔记本电脑上使用 PGP 磁盘加密产品（并在其上运行 NTFS 压缩！）。如果要读取的磁盘量很小的话，似乎没有太大的影响；按照磁盘标准，大多数软件源并不大。
你有大量的内存和相当快的处理器。我大部分时间都在思考，
打字或调试。
我不会太担心它。
I used to use the PGP disk encryption product on a laptop (and ran NTFS compressed on top of that!). It didn't seem to have much effect if the amount of disk to be read was small; and most software sources aren't huge by disk standards.
You have lots of RAM and pretty fast processors. I spent most of my time thinking,
typing or debugging.
I wouldn't worry very much about it.
我当前的工作机器配备了 Bitlocker，并且是之前型号的升级版。对我来说，它只是看起来更快。然而，我发现，在准确放置数据方面，bitlocker 比 truecrypt 更防弹。我在 SAS 中做了很多工作，它在移动时不断将备份副本写入磁盘，并最终将各种输出类型写入磁盘。 SAS 可以很好地将多线程进程的输出写回 Bitlocker，并且似乎不知道它在那里。对于我来说 truecrypt 的情况并非如此。我不确定发生了什么或如何发生，但我发现在处理 truecrypt 容器中的源/输出数据时，进程不同步，这是我在第二台工作计算机上安装的容器，因为它没有 bitlocker。持续备份拍摄到 SSD，而 truecrypt 结果保存在普通 HD 上。也许正是这种速度差异导致了问题的发生。不管是什么原因，我不得不停止在第二台计算机上使用 truecrypt，因为它使我的 SAS 结果与处理顺序不同步，并且搞砸了我的一些流程和数据。我的世界里有可怕的东西。
我与在同一台计算机上成功使用 Truecrypt 的人一起工作，但他们没有使用磁盘密集型应用程序。像SAS。
Bitlocker to Go（Bitlocker 应用于拇指驱动器的加密）在读/写时间方面确实会减慢很多速度。只要您记住拇指驱动器上的密码，并且愿意等待它格式化/初始化驱动器，使用它并不太难，但根据我的经验，它使访问闪存驱动器的速度慢了大约 4 倍。不知道为什么它会减慢拇指驱动器而不是磁盘的速度，但这对我和我的同事来说就是这样。
基于我在工作中使用 Bitlocker 取得的成功，我为我的家用计算机购买了 Windows Pro 以获得 Bitlocker，并计划用它加密一些目录，例如财务等。
My current work machine came with bitlocker, and being an upgrade from the prior model. It only seemed faster to me. What I have found, however, is that bitlocker is more bullet proof than truecrypt, when it comes to accurately laying down the data. I do a lot of work in SAS which constantly writes backup copies to disk as it moves along and shoots a variety of output types to disk at the end. SAS works fine writing output from multithreaded processes back to bitlocker and doesn't seem to know it's there. This has not been the case for me with truecrypt. I'm not sure what happens or how, but I found that processes got out of synch when working with source/output data in a truecrypt container, which is what I installed on my second work computer since it had no bitlocker. The constant backups were shooting to an SSD while the truecrypt results were on a regular HD. Maybe that speed difference helped trip it up. Whatever the cause, I had to quit using truecrypt on that second computer because it made my SAS results out of synch with respect to processing order and it screwed up some of my processes and data. Scary stuff in my world.
I work with people who have successfully used Truecrypt on the exact same computer, but they weren't using a disk intensive app. like SAS.
Bitlocker to Go, the encryption which bitlocker applies to thumb-drives, does slow things down quite a bit when it comes to read/write times. It's not too hard to use as long as you remember your password on the thumbdrive, and are willing to wait for it to format/initialize the drive, but in my experience it made access to the flash drive about 4 times as slow. Don't know why it would slow down a thumb drive and not a disk but that's how it was for me and my coworker.
Based on my success with bitlocker at work, I bought Windows Pro for my home computer to get bitlocker and plan to encrypt some directories with it for things like financials.