A security feature that comes with Windows 11 Pro can severely impact the performance of your solid-state drive. Fortunately, it's easy to turn off, but some people don't know that it's enabled by default. The BitLocker encryption feature in Windows 11 Pro is designed to protect data security and ensure that only authorized people can access the data, but it also brings serious performance losses.
To find out how big an impact it has, Tom's Hardware recently conducted tests in three scenarios: unencrypted (no BitLocker), software-enabled BitLocker (Windows 11 Pro default), and hardware-based BitLocker.
The test used a 4TB Samsung 990Pro SSD running Windows 11 Pro (22H2, all patches installed), paired with an Intel Core i9-12900K and 32GB DDR4 memory.
In PCMark10's storage benchmark, the software-enabled BitLocker configuration was 20 percent slower than the hardware-encrypted and unencrypted configurations. Similar slowdowns were observed in CrystalDiskMark's random read test, while Tom's performance dropped a massive 45% in the random write test. In DiskBench's 50GB copy transfer test, the software-supported BitLocker setting was 11% slower.
The good news is that the hardware-based setup behaves consistently as without any encryption running. If you insist on using encryption, that's certainly the best option.
If you want to learn more, you can find the full test results on Tom's Hardware:
https://www.tomshardware.com/news/windows-software-bitlocker-slows-performance
They also outline how to tell if encryption is running and how to disable it. In short, if you are running Windows 10 Pro, encryption may not be enabled; if you are using Windows 11 Home, encryption is definitely not enabled; if you are using Windows 11 Pro, please check as it may already be enabled by default.
Also, it's worth noting that the hard drive and CPU you're using may vary. A much less powerful chip than the Intel Core i9-12900K used by Tom's Hardware would probably perform even worse.