M.2 interface
To test the speeds of the PCIe, M.2 SSD that ships with the XPS 13, I ran CrystalDiskMark and ATTO Disk Benchmark.
Interesting results here: the ‘read' speeds are quite high at around 1700 MB/s, but ‘write' speeds of around 430 MB/s are comparatively slow, especially for a PCIe drive. This should not make much difference to most consumers, as the XPS 13 is not aimed at those likely to be writing large files on a regular basis.
USB 3.0 bandwidth
To test the XPS 13’s USB 3.0 Type-A ports, I plugged in an OCZ Trion 150 SSD via a SATA-to-USB 3.0 5Gbps adapter, which uses the ASMedia ASM1053 controller. We reviewed the SSD HERE, finding it delivers good speed at a budget price. Most importantly, it is capable of saturating the USB 3.0 bus, allowing us to test the speeds the two USB 3.0 ports delivers. To test this, I ran both CrystalDiskMark and ATTO Disk Benchmark on the Trion 150 drive.
As we would expect, the USB 3.0 results are right at the limit of the 5Gbps ceiling.