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O&O Defrag vs Smart Defrag: catalog facts
O&O Defrag	Smart Defrag
Paid Commercial software sold by O&O Software.	Free Offered by IObit as a free download.
Windows	Windows
Optimizes drives automatically in the background Maintained by an established Windows software vendor	Defragments hard drives and optimizes SSDs Targets boot time as well as general disk layout
Windows only Paid software	Windows only Closed source
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 September 24, 2026	Official website Full listing and sources Checked October 1, 2026

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