regular USB C Extension cable (3.3ft/1m) works at 10Gbps-TB1 speed on TB3 system
I have been using a caldigit 2m TB3 cable for most of my games and it works fine for the games I run. I don't care if I can't get 70fps, as long as I can get 60fps then it really doesn't matter to me if the cable doesn't have enough bandwidth for an FPS that's above my refresh rate.. doesn't make sense. Anyways, I grabbed a 3 foot USB c extension from my bag and to my surprise it works great. Well.. it works but I get under a GB/s for H2D but overwatch doesn't care at all. At ultra, I get 60fps even via my internal screen with this cheapo extension cable.
Just wanted to let everyone know
Benchmark Numbers: Heaven at max settings 1080
Caldigit: 60.7FPS Optimus - 72.1 External - 1.5GB/s H2D 1.6GB/s D2H
Caldigit + Extension: 49.7FPS Optimus - 72.3 External - 867MB/s H2D - 865MB/s D2H
Sonnet Cable: 67.5FPS Optimus - 75.2 External - 2.6GB/s H2D 2.8GB/s D2H
Sonnet Cable + Extension: NA - NA - NA (Didn't work)
Just played a couple games of Overwatch after I posted this. Hasn't crashed... success!!
I'm very surprised it worked. We can think of USB-C extension as 10Gbps TB3 cable then.
The speeds seem to fluctuate based on how much power the laptop draws? When my laptop is charging it can drop down to 600MB/s and then when it's fully charged, it'll jump back up to 820MB/s ish. Weird but It's 100% stable so this is a good solution for people looking for better docking performance with more monitors and not looking to game. This reduced bandwidth doesn't affect adobe premiere either. I have another version of an extension cable that I also want to try.
Overwatch in optimus mode still runs at 60FPS no problem. I see the usage around 30% in GPUz versus 15% using the caldigit cable. Make sense
Another observation. The extension has to be attached to the computer side. If it's attached to the TB3 endpoint, it charges but doesn't connect.
Pretty cool discovery.
@miah_adib, No, he's saying you can use a USB-C cable instead of a Thunderbolt cable, but your computer needs a Thunderbolt controller to use an eGPU. The USB-C cable will be slower than a Thunderbolt cable.
@miah_adib, Please stop posting the same question about your USB-C only laptop. It will not work with a Thunderbolt 3 eGPU.
You may be able to use an M.2 eGPU adapter such as the ADT-Link R43SG.