GTX 1080 TB3 eGPU for 2019 Lenovo S740 15IRH (GTX1650) [9th,6C,H]?
Hello, I currently own the Lenovo s740 15inch model and I really want to attach my GPU (GTX 1080) via TB3 connection (my desktop CPU is getting old) but I have a few questions:
1. My laptop doesn't support TB3 charging so if I'm connecting a box that can drive for example, 100W, will this pose a risk for my laptop?
2. Some TB3 connection share the 4 PCIe lanes with devices like Storage, LAN etc. How can I check that my 4 lanes aren't being shared?
Hello @anthon_naivelt and welcome to the forum.
1. Thunderbolt charging protocol dictates that the device requesting power indicates how much power it requires. If your laptop does not support charging via USB-C / Thunderbolt 3, it will not request any power and none will be provided. No issues here.
2. I believe the s740 series has 4 lanes of PCIE dedicated to its Thunderbolt 3 ports, much like the s730 did. If four lanes are dedicated to the Thunderbolt 3 ports, they will not be shared with other devices, but the s740 will have all its peripherals run via the PCH, including the Thunderbolt 3 ports. While this does slightly decrease the absolute performance potential of an eGPU when compared to a device that has its Thunderbolt Controller embedded in the CPU, it doesn't mean that an eGPU isn't a route to increased performance.
You will see a good performance gain running a GTX 1080 via an eGPU over the built in 1650 Max-Q or Intel UHD in the s740.