Yes, the Lexar Professional 1667x 64GB SD is compatible with the Sony A7 IV.
The lexar professional 1667x 64gb sd is an SDXC UHS-II V60 card. V60 clears the A7 IV's standard and S&Q 4K modes but not XAVC S-I 4K/HD, which require V90. Records most modes, not the high-bitrate intra-frame ones.
Limitation
Cannot record XAVC S-I 4K (intra-frame) -- requires Video Speed Class V90 per Sony's own spec, this card is V60. Works for XAVC HS/S 4K (V30 required, met) and all lower-bitrate modes via the SD slot.
“XAVC S-I 4K 600Mbps CFexpress Type A memory card (VPG200 or higher) SDXC V90 or higher”
“Faster Video Capture With V60 Class For Professional Users”
Last verified:
Compatibility inferred from spec rule (citations above are manufacturer-verified)