As many on this and other subreddits, I've struggled quite a bit with various cables to connect my eGPU (Razer Core X Chroma). And of course, the issues were occuring whenever I tried using 2m long ones.

None of the Thunderbolt cables I bought off Amazon did the trick. I was mainly relying on CUDA-Z to confirm the negotiated speeds:

Short cables, incl. original cable that came with the eGPU: 2100 / 2700 MBps (16.8 / 21.6 Gbps).
Longer 2m active TB4 cables: 1400 / 1750 MBps (11.2 / 15 Gbps).

[UPD:] Corrected Mbps to MBps, this was an obvious mistake.
Max. speed expected from TB3 in data-only mode is 22 Gbps [LINK], which after division by 8 gives us max. speed of 2750 MBps. 22Gbps = 22000 Mbps = 2750 MBps.

The only 2m cable that was on par with short ones was an old Razer Thunderbolt 3 cable I found on a local used electronics market (p/n RC21-01270101-R3M1). However, this cable cannot deliver enough power to my laptop, which throttles the CPU. This was not the case with other cables, so the problem was not on the eGPU side.

Question: has anyone benchmarked Razer Thunderbolt 4 Cable (2m version)? What speeds does it actually deliver? Razer website states "40 Gbps" without even the "up to", but I have some serious doubts about its performance.

[UPD2:] Here is the info from CUDA-Z for the 4 cables that I currently have on hand. Using LG Gram (2022, Intel 12th Gen CPU) with Razer Core X Chroma and Asus Nvidia RTX 4070 Ti SUPER:

1. Razer Thunderbolt 3 cable: 2m [RC21-01270101-R3M1]
Note: purchased on aftermarket, came in original Razer box

r/eGPU - Razer Thunderbolt 4 Cable (2.0m / 6.56ft)

2. Razer Thunderbolt 3 cable: 50cm [Core X Chroma stock cable]

3. Plugable Thunderbolt 3 cable: 80cm [‎TBT3-40G80CM]
Note: purchased on Amazon from official Plugable store

4. Cable Matters Thunderbolt 4 cable: 2m [model number on Amazon page:430315031]
Note: purchased on Amazon from official Cable Matters store

5*. Plugable Thunderbolt 4 cable: 2m [‎TBT4-40G2M]
I have returned this one and did not save the screenshot from CUDA-Z. However, the reason for return was due to low speed - it was on par with Cable Matters 2m cable. Originally ordered off Amazon from the official Plugable store.