Thunderbolt 3 40gbps Data Transfer Rate

Customers using Dell systems with a Thunderbolt 3 port may report they are unable to achieve data transfer rates up to the maximum 40gbps. Some customers may report the data transfer speeds vary depending on the system they are testing on.

Customers may also report that the system only has 2 lanes of data and not the expected 4 lanes. See the chart below on which systems were designed with 2 lanes and which were designed with 4 lanes.

Note: Any system that is not listed in the article should be 4 lanes as Intel has standardized to 4 lanes.

Platform Lanes of PCIe capable via Thunderbolt 3 port Dell Precision 3510 * 4 lanes Dell Precision 3520 * 4 lanes Dell Precision 5510 2 lanes Dell Precision 5520 2 lanes Dell Precision 7510 4 lanes Dell Precision 7520 4 lanes Dell Precision 7710 4 lanes Dell Precision 7720 4 lanes XPS 12 2-n-1 2 lanes XPS 13 9365 2-n-1 4 lanes XPS 13 9350 2 lanes XPS 13 9360 2 lanes XPS 13 9370 4 lanes XPS 15 9550 2 lanes XPS 15 9560 2 lanes Latitude 7275 4 lanes Latitude 7285 4 lanes Latitude 5570 * 4 lanes Latitude 7370 4 lanes Latitude 7280 4 lanes Latitude 7480 4 lanes Latitude 5480 4 lanes Latitude 5580 4 lanes Alienware 13 R2 2 lanes Alienware 15 R2 4 lanes Alienware 17 R3 4 lanes Alienware 13 R3 4 lanes Alienware 15 R3 4 lanes Alienware 17 R4 4 lanes Inspiron 7577 4 lanes

* Only select configurations have Thunderbolt 3 ports.

Thunderbolt 3 ports can be configured with 2 or 4 PCIe lane designs. Note that Alpine Ridge uses separate inputs for Display Port 1.2 data (DP stream is not part of PCIe traffic).

Thunderbolt 3 bandwidth is shared bandwidth which means all connected devices use the bandwidth for all protocols that transfer through the same Thunderbolt 3 cable (DisplayPort over USB-C traffic and PCIe traffic such as USB, Ethernet, and Audio). Below is a chart that can help explain how different items can use the 40gbps total bandwidth. The Dell Thunderbolt TB16 dock can utilize up to the full 40 Gbps of bandwidth depending on what devices are attached to the TBT dock.

Port Version Throughput Output HDMI 1.4 10.2 Gbps Up to 4K2K @ 30 Hz true color Mini Display Port 1.2 Up to 16 Gbps per lane Up to 4K2K @ 60 Hz Full-Size Display Port 1.2 Up to 16 Gbps per lane Up to 4K2K @ 60 Hz VGA RJ-45 IEEE 802.3 10/100/1000 Mb/s USB (2) 2.0 Type A 480 Mbps 5 V @ 500 mA, 2A Peak USB (2) 3.0 Type A 5 Gbps 5 V @ 900 mA, 2A Peak USB w/Powershare (1) 3.0 Type A 5 Gbps 5 V @ 2A Power Share USB Type-C Thunderbolt™ Gen 3 Up to 40 Gbps Up to 60 W*

For more information please visit the link: https://thunderbolttechnology.net/sites/default/files/Thunderbolt3_TechBrief_FINAL.pdf

NOTE: Systems with the 2 lane design will only support up to 20gbps data transfers over PCIe devices such as external hard drives or PCIe video cards. Systems with 4 lane design will support up to 40gbps of data transfer over PCIe depending on the device in use.

If you have further questions about this article, contact Dell Technical Support.