iTunes 12.10.11 for Windows (Windows 64 bit) - Apple Support
iTunes 12.5.5 for Windows 64-bit was a solid, performance-oriented update in its time, bringing meaningful 64-bit optimizations and iOS 10.3 support. However, it is now a legacy tool. Users seeking stability and modern features should upgrade to the latest iTunes or migrate to Apple’s new Windows media apps. itunes 12555 for windows 64bit new
1GHz Intel or AMD processor with support for SSE2. iTunes 12
This version arrived during the transition to macOS Sierra and iOS 10, aimed at providing "minor app and performance improvements" for both Mac and Windows users. For Windows 64-bit users, it became a "rescue" version for those facing bugs in newer updates, such as the sluggishness reported in version 12.6. Key Features of this Era 1GHz Intel or AMD processor with support for SSE2
Leo’s computer had been acting strange for weeks. Not glitchy—strange. Old MP3s he’d ripped from scratched CDs in 2007 would suddenly play at half-speed. Album art from obscure 90s techno compilations would flicker over his dad’s country western playlists. His mouse cursor would drift toward the iTunes icon on its own, as if the software was lonely.
iTunes on Windows has always been a bit of a "heavy" application—it takes up space and can be sluggish. However, iTunes 12.5.5 for Windows 64-bit represented a solid step forward in stability for users with large libraries and newer iPhones.