Yes, the Lexar Professional 1667x 64GB SD is compatible with the Nikon Z6 III.
Nikon's official Z6 III manual: cards rated UHS Speed Class 3 or better are recommended for standard video recording/playback (45 MB/s tier); high frame-size/rate video needs a U3 card sustaining >=250 MB/s. Lexar 1667x writes 120 MB/s -- clears the standard floor, fails the high-frame-rate floor -- corrected 2026-06-21, previous verdict cited an unsourced flat "250 MB/s for 4K60" floor that doesn't distinguish standard vs. high-frame-rate modes.
Limitation
Standard video recording works -- 120 MB/s clears Nikon's 45 MB/s / UHS Speed Class 3 floor. Cannot sustain Nikon's high frame-size/rate 4K modes, which require an SD card benchmarking at least 250 MB/s (Nikon's own published floor, not a Speed Class rating) -- this card benchmarks 120 MB/s.
“UHS Speed Class 3 or better SD cards with a maximum data transfer rate of at least 250 MB/s, are recommended for recording and playback of videos with a high frame size or rate.”
Last verified:
Compatibility inferred from spec rule (citations above are manufacturer-verified)