The Angelbird Wings PX1 M.2 Adapter Review: Do M.2 SSDs Need Heatsinks?

Sequential Write

Sequential writes are easier for the SSD controller to process than random writes, so throughput is almost always higher and the bottleneck in this test shifts more to the flash itself. This test puts the most intense load on the flash out of any of our tests, and usually produces the highest overall power consumption. The timing of the sub-tests is the same as for the random tests, and the drive is filled before the test so that features like SLC write caching don't distort the beginning of the test.

The heatsink provides a nice boost to the 256GB 950 Pro's sequential write speed, but doubles the sustained performance of the 512GB model. Power efficiency is still improved, especially for the 512GB drive, but it's now reaching almost 6W.

256GB no heatsink	512GB no heatsink
256GB with heatsink	512GB with heatsink

Without the heatsink, both drives experience thermal throttling only a few minutes into the test, with QD2 performance lower than QD1. With the heatsink, both drives show steady performance across the entire test. The 256GB improves QD1 performance slightly while the 512GB drive sees a 73% increase in QD1 performance. At queue depths greater than one the performance improvements are even larger.

Sequential Read

With the lower overhead of sequential operations and the inherent speed advantage reads have over writes, the sequential read test usually produces the highest throughput numbers. For SATA drives nowadays this usually means the SATA interface itself is the bottleneck, but even with NVMe we haven't seen a drive yet saturate the bandwidth of a PCIe 3.0 x4 link. Depending on the drive, this test could be limited by bottlenecks in the SSD controller's host interface or its connections to the flash memory.

Both capacities see significant gains in sequential read performance, accompanied by smaller but still significant increases in power consumption. The 512GB drive once again manages to double sustained performance, and the 256GB improves by 58%.

256GB no heatsink	512GB no heatsink
256GB with heatsink	512GB with heatsink

Again we see that the drives can't scale with higher queue depths when they're thermally constrained, but when properly cooled they perform superbly with any queue depth larger than one. The 512GB drive manages to deliver slightly more than 2.6GB/s read speed, well above what can be achieved with PCIe 2.0 x4 and about two thirds of the capacity of the PCIe 3.0 x4 link used by the 950 Pro.