Yes, the Sony Alpha A7R V is compatible with the Transcend 700S V90 64GB.
Transcend 700S V90 is V90 class. Clears: XAVC HS 4K (200 Mbps, requires U3); XAVC S 4K (200 Mbps, requires U3); XAVC S HD (100 Mbps, requires U3); XAVC HS 8K (400 Mbps, requires V60); XAVC S-I 4K (600 Mbps, requires V90); XAVC S-I HD (222 Mbps, requires V90).
“XAVC HS 8K 400Mbps SDXC V60 or higher XAVC HS 4K / XAVC S 4K / XAVC S HD 200Mbps / 200Mbps / 100Mbps SDHC/SDXC card (U3 or higher) XAVC S-I 4K / XAVC S-I HD 600Mbps / 222Mbps SDXC V90 or higher”
Last verified:
Compatibility inferred from spec rule (citations above are manufacturer-verified)