What are the differences between a 32-bit and a 64-bit registry?

The registry is a database containing configuration settings and options that Windows uses to manage its OS, hardware and software. It is an integral part of the Windows operating system and has been present since the introduction of Windows 95.

The main difference between 32-bit and 64-bit registry entries is the amount of memory they can address. 32-bit computers use 32-bit registry entries, which can only address up to 4GB of RAM. In comparison, 64-bit computers use 64-bit entries, which can address up to 16 exabytes (16 billion gigabytes) of RAM. This increases the amount of information that can be stored in the registry and consequently improves overall performance.

There are also several other differences between 32-bit and 64-bit registry entries. For starters, the location of the registry file itself is different. In a 32-bit system, the registry is located in the System32 folder, while the registry in a 64-bit system can be found in the SysWOW64 folder. Secondly, 32-bit systems use .reg files for registry data, while 64-bit systems use .reg files for legacy 32-bit software and .regedit files for 64-bit software.

In terms of user access, 32-bit systems grant more access than 64-bit systems. On a 32-bit computer, users can modify their own registry data as well as the data of the root user and other administrator accounts. However, on a 64-bit computer, users are restricted from modifying the registry data of root users and other administrators. This is done in order to provide extra security.

Finally, 32-bit and 64-bit registry entries use different formats. The 32-bit registry uses the Windows Registry Editor Version 5.0 (REGEDIT5) format, while the 64-bit registry entries use the Windows Registry Editor Version 6.0 (REGEDIT6) format. These two formats are not compatible with each other, so any registry modification must be done using the appropriate format.

Overall, 32-bit and 64-bit registry entries differ in various ways, such as the type of information they can contain, the format they use, and the level of user access they grant. Therefore, it is important to understand these differences when making modifications to the registry.