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Smart Defrag vs O&O Defrag: catalog facts
Smart Defrag	O&O Defrag
Free Offered by IObit as a free download.	Paid Commercial software sold by O&O Software.
Windows	Windows
Defragments hard drives and optimizes SSDs Targets boot time as well as general disk layout	Optimizes drives automatically in the background Maintained by an established Windows software vendor
Windows only Closed source	Windows only Paid software
Downloadable app	Downloadable app
Closed source	Closed source
License not stated	License not stated
Not stated if an account is needed	Not stated if an account is needed
Works offline	Works offline
Official website Full listing and sources Checked October 1, 2026	Official website Full listing and sources Checked September 24, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.