Fast File Validator (FFV) is a program for verifying files against a checksum file and for creating such checksum files. (I’m using checksum in the generic sense. Technically, neither CRC32 nor MD5 is really a checksum.)
FFV supports both SFV files (which use the CRC32 algorithm) and MD5 files. Actually, it can handle both types of checksum in the same file, although you don’t normally see this, and I don’t recommend creating such files.
FFV is fast, because it’s written directly to the Win32 API to avoid unnecessary overhead and it uses a multi-threaded design, so it can calculate the CRC while reading the file. (Note: In my limited tests, it’s about 40% faster under NT 4.0 than under Windows 98, reading the same files off the same hard drive.)
I would like to hear from anyone who uses FFV, especially if you find it useful. You can find my contact information here.