3 ms·

Yes, but for people thinking of going down this path, the cables are $120 and pretty thick so it’s not without trade offs

Teknoman117 4y ago
Not really. $120 for the Apple branded two meter cable for sure, but the third party ones run about $30/meter. I bought a handful of the one meter "Cable Matters Thunderbolt 4 40 Gbps" cables off Amazon for $30 each. I run one from a Dell XPS 15 laptop pulling up to 100W to a dock. They are quite chunky though. Beware anything longer than 2 meters that isn't an active cable though. The differential lanes will probably drop to 10 Gbps. Fine for USB 3, 3.1, and 3.2x2 but you'll lose half the USB4 bandwidth. --- I'm not sure if Thunderbolt allows for lane speed degradation. You see some "thunderbolt 3 20gbps" cables but I don't know if that's two pairs at 10 Gbps or one pair at 20 Gbps. Now you've got this whole USB4 mess - USB 4 and Thunderbolt 4 are the exact same protocol and physical layer, same controllers and everything. The difference is whether the device or host adheres to the performance specification and paid for certification.
- edude03 4y ago
  My information is out of date then thanks for the heads up. Yes the last TB cable I bought was the apple one, but prior to that I purchased Belkin and Startech cables for the same price and couldn't find cheaper ones
- causality0 4y ago
  Thirty dollars for a three foot cable still sounds like highway robbery to me.
  - NavinF 4y ago
    Not really, this is just what happens when you use copper for 40gbps. Consider that 1 meter QSFP DACs are also $30. $/m gets a lot cheaper with longer fiber cables. They're more flexible too
    - Teknoman117 4y ago
      > $/m gets a lot cheaper with longer fiber cables. They're more flexible too Pretty much. The cost of the optics amortizes at a certain length. You also don't have to worry about breaking something super expensive if you accidentally damage the fiber (for shorter runs). Consider some of the DAC cables for the new 800 GbE standard cost $1300 for a 2 meter cable.
  - Teknoman117 4y ago
    We're not just talking about a random wire through a cable at this point. Transmitting multi-gigahertz signals through a copper conductor is complicated. These types of signals are extremely vulnerable to the impedance of the cable, capacitive losses, etc. Producing a cable that stays in spec over some large arbitrary length while taking the abuse of being wiggled around all the time is expensive.

Teknoman117 4y ago

Not really. $120 for the Apple branded two meter cable for sure, but the third party ones run about $30/meter. I bought a handful of the one meter "Cable Matters Thunderbolt 4 40 Gbps" cables off Amazon for $30 each. I run one from a Dell XPS 15 laptop pulling up to 100W to a dock. They are quite chunky though. Beware anything longer than 2 meters that isn't an active cable though. The differential lanes will probably drop to 10 Gbps. Fine for USB 3, 3.1, and 3.2x2 but you'll lose half the USB4 bandwidth. --- I'm not sure if Thunderbolt allows for lane speed degradation. You see some "thunderbolt 3 20gbps" cables but I don't know if that's two pairs at 10 Gbps or one pair at 20 Gbps. Now you've got this whole USB4 mess - USB 4 and Thunderbolt 4 are the exact same protocol and physical layer, same controllers and everything. The difference is whether the device or host adheres to the performance specification and paid for certification.

edude03 4y ago
My information is out of date then thanks for the heads up. Yes the last TB cable I bought was the apple one, but prior to that I purchased Belkin and Startech cables for the same price and couldn't find cheaper ones
causality0 4y ago
Thirty dollars for a three foot cable still sounds like highway robbery to me.
- NavinF 4y ago
  Not really, this is just what happens when you use copper for 40gbps. Consider that 1 meter QSFP DACs are also $30. $/m gets a lot cheaper with longer fiber cables. They're more flexible too
  - Teknoman117 4y ago
    > $/m gets a lot cheaper with longer fiber cables. They're more flexible too Pretty much. The cost of the optics amortizes at a certain length. You also don't have to worry about breaking something super expensive if you accidentally damage the fiber (for shorter runs). Consider some of the DAC cables for the new 800 GbE standard cost $1300 for a 2 meter cable.
- Teknoman117 4y ago
  We're not just talking about a random wire through a cable at this point. Transmitting multi-gigahertz signals through a copper conductor is complicated. These types of signals are extremely vulnerable to the impedance of the cable, capacitive losses, etc. Producing a cable that stays in spec over some large arbitrary length while taking the abuse of being wiggled around all the time is expensive.