Dell XPS 17 9700
I was thinking about getting this laptop. Like the Apple MBP’s, the Dell XPS 17 has 4x thunderbolt ports, 2 on the left and 2 on the right. What isn’t clear to me is how the PCIe lanes are assigned here. I would like to think that there are 2X thunderbolt controllers, but I wouldn’t put it past Dell to try and make all 4 ports share the one 40Gbps bus. Does anyone know? I contacted Dell support and the person I talked to obviously was misinformed: he claimed all 4 ports could deliver 40 Gbps simultaneously. 160Gbps!? Really!? 🤣😂🤣😂🤣
The Dell XPS 17 9700 has 10th gen Ice Lake CPU with integrated Thunderbolt. There's no PCIe between the CPU and the Thunderbolt controller(s).
Read about Ice Lake Thunderbolt PCIe bandwidth at:
Total PCIe bandwidth of all four ports is around 38 Gbps (from the 4778 MB/s that @itsage was able to achieve - ~20 Gbps for a single port but some benchmarks might see 22 Gbps).
You can add two DisplayPort 1.2 displays (17.28 Gbps each but I could only get up to a max ~16.4 Gbps each with my Mac mini 2018).
Maybe you can do two DisplayPort 1.4 displays (each to a different port) (25.92 Gbps each so maybe ~25 Gbps achievable max?) since Ice Lake Intel GPU supports DisplayPort 1.4 but there might be a limit on the total number of pixels per second...
So while all four ports can each do 40 Gbps, the max bandwidth on all 4 ports together is between 70 Gbps and 90 Gbps (when including DisplayPort outputs).
For PCIe traffic, the setup of the Ice Lake Thunderbolt controllers is better than dual discrete Thunderbolt controllers because you can RAID any two Thunderbolt ports together without hitting the ~23 Gbps limit of a single discrete Thunderbolt controller. The limit from raiding four ports of dual discrete Thunderbolt controllers will be 23 Gbps x 2 (= 46 Gbps) or less - it is unknown if it can beat the 38 Gbps limit of four ports from Ice Lake. Anyway, I don't know of any PC laptops with dual discrete Thunderbolt controllers.
Remember that Thunderbolt can send and receive at the same time. I added the higher D2H numbers of the PCIe tests with the H2D numbers of DisplayPort but I should do H2D for both which would lower the PCIe numbers slightly - but maybe there exists a PCIe device that has a higher H2D number compared to D2H?
Thanks for the thoughtful reply. I was mainly asking, because I want to try 2x eGPU’s but would like to give each eGPU as much bandwidth as possible. I was doing this with dual 1080’s in eGPU’s on a MacBook Pro with 4x TB3 ports.