G-Drive mobile pro Thunderbolt 3 500GB SSD underperformance

The drive gets nowhere near the advertised 2800 MB/s sequential speeds when attached with a 40GBit/s cable (tried the one it came with, 0.8m Apple Thunderbolt 3 cable and a 0.5m Belkin Thunderbolt 3 cable) to an iMac Pro and to a 15 inch MacBook Pro 2017. Both Blackmagic and AJA report 1300 MB/s sequential write and 1500 MB/s read speeds. SSD Review (G-Technology G DRIVE mobile PRO SSD (1TB) Review | The SSD Review) was able to get advertised speeds on the 1TB version of the drive.

Is the 500GB version of the drive gimped, or is this underperformance specific to Macs?

Not sure what might be causing the issue you are experiencing. My own personal tests put the lowest transfer rate on the 500GB unit at about 2000MB/s and the 1TB 2500+ pretty easily using an early 2017 MBP. This is just using the supplied cable.

Thank you for getting back to me. I tried running Blackmagic benchmark again on a 2017 MBP with a freshly installed OS and nothing else running. I obtained the same results - roughly 1300/1500 MB/s write/read sequential speeds. Could the drive be defective?

Thanks.

Yes, We would recommend a replacement unit.