Sony SF-G Series 64GB UHS-II U3 Class 10 SDXC Memory Card, Maximum 300 MB/s Read and 299 MB/s Write Speed

Sony announced SF-G UHS-II memory cards in in February 2017 and promoted their 300MB/s read speed and 299MB/s write speed. The write speed was the highest speed of any UHS-II card to date. The G Series card carries a U3 speed rating meaning it is capable of continuous write speeds of at least 30MB/s making it suitable for recording HD and 4K video. The SF-G cards are available in 32, 64 and 128 GB capacities. This review covers the 64GB SDXC card, model SF-G64/T1 with UPC 027242904330. The card tested is marked Made in Taiwan on the back.

While UHS-II cards claim extremely high transfer rates, these speeds require a UHS-II interface. The cards are backwards compatible and will operate in Standard SD and UHS-I modes although their speed will be limited when used in such devices. The UHS-II interface requires a second set of pins to communicate in the high-speed UHS-II bus mode. Devices lacking those connection will connect to the card using the standard row of SD contacts and will be limited to UHS-I or lower speeds. In UHS-I mode the SF-G card supports SDR104 bus mode which is limited to 104MB/s.

The 64GB Sony SF-G UHS-II card was benchmarked in several USB 3.0 card readers. In UHS-II mode the card measured up to 298.3 MB/s sequential read speed. The card posted a 273.4 MB/s sequential write speed in the fastest test. The write speed was slightly lower than expected given the 299MB/s speed claimed by Sony.

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