[trevorishere]

However, by default on NTFS, there will be 4096-N bytes of used space each time the specific hive needs to grow to accommodate those 10-100 bytes (this varied historically if we're talking about NT 4 and below, depending on volume size) due to format cluster size.

That said, it is still smaller than 100 files that are 10-100 bytes each taking up 4096 bytes, though with NTFS, those would be stored in the MFT anyways...

[trevorishere]

I should add to this, as we know file system filters (e.g., anti-virus) slow down access to read (and write, but irrelevant here) files from any file system format on Windows (NTFS, FAT32, exFAT, etc), storing configuration data in configuration files would be less optimal, though minimal in terms of performance (given your app wasn't constantly re-reading the file). This wouldn't be the case with the Registry, as the hives are already open.