The ADT R27A-BK3 is an inexpensive way to add a U.2 NVMe SSD to a system that only has standard PCIe slots. We have been testing the EDSFF version of this adapter family, and we wanted to see how the U.2 variant works since it uses a different connector and drive form factor.
You can find what we purchased on Amazon (affiliate link) or AliExpress (Affiliate link). There are different versions, including an EDSFF version we previously reviewed, so make sure you are buying the correct model.
ADT R27A-BK3 U.2 to PCIe Adapter Review
The metal shell is fairly large because it has to enclose a full-length U.2 drive, a blower fan, and the adapter PCB.
Along the top, there is just the metal cover. The shell provides structural support and helps direct airflow over the drive.
The I/O plate mostly holds the card in place and provides vents for airflow.
The rear of the unit has screws and a fan cable with a standard 4-pin PWM connector.
The bottom edge carries a PCIe Gen5 x4 gold-finger connector. ADT also sells a Gen4 version of this adapter, so check which generation you need before ordering.
Removing the cover requires a few screws, and then we can see what is inside.
First, there is the 4-pin PWM blower fan. The board is labeled as a PCIe x4-to-U.2 SSD adapter with an SFF-8639 connector.
The adapter uses an SFF-8639 connector, which means it is designed for U.2 drives only. This is a key difference from the EDSFF version we reviewed earlier, which used an SFF-TA-1002 connector for E1.S and E3.S drives.
Next, let us get some drives in the unit so you can see what this looks like. We used a Samsung PM9D3 U.2 SSD for testing.
The fan is important here because the drive sits inside an enclosed shell. In our testing, we did not see the same thermal throttling behavior we saw with the EDSFF version of this adapter.
ADT R27A-BK3 Performance
We tested two different drives in the ADT R27A-BK3 to see how it handles varying interface generations and thermal loads. The first drive is a Samsung MZQLB7T6HMLA-00007, which is a 7.68TB U.2 SSD using a PCIe Gen3 x4 interface.
During a 20-minute run, the Samsung drive peaked at 2,252 MB/s and sustained 2,179 MB/s. This represents a roughly 3.2% drop from peak to sustained performance. Throughput dropped slightly around the eight-minute mark but then held steady near 2.18 GB/s for the rest of the test. Temperature peaked at 78 C, staying well below the drive’s warning threshold of 86 C.
The second drive tested was a Solidigm D7-PS1010, also in a 7.68TB capacity but using a much faster PCIe Gen5 x4 interface. This test focused on sustained 128K sequential writes to stress the adapter and cooling solution under high bandwidth conditions.
The Solidigm drive achieved a peak throughput of 7,946 MB/s and sustained 7,838 MB/s over the same 20-minute duration. The performance drop from peak to sustained was minimal at just 1.4%. While the chart shows brief dips in throughput, the drive quickly returned to approximately 7.8 GB/s. Temperature leveled off at 70 C, well below its warning threshold of 77 C.
Neither drive exhibited sustained thermal throttling during the 20-minute runs. Both drives remained below their respective warning temperature thresholds throughout the runs. So the cooling on this one isn’t too bad, but if you have a hotter drive, you might want to trust it, but verify it is working in your machine.
Final Words
The ADT R27A-BK3 is a straightforward way to add a U.2 NVMe drive to a system without native U.2 support. The included fan and metal shell help keep the drive cool, and we did not observe thermal throttling during our testing.
Just make sure you buy the correct version for your drive type. This R27A-BK3 is specifically for U.2 SFF-8639 drives, while the EDSFF variant uses a different connector and is sold under a different model number.
