4 ms·

I'm very interested in your use case where 40Gbit/s is not more than enough.

by bzzzt 2y ago

pier25 2y ago
You don't really have 40gbits for data transfer in tb3/4. A good chunk is reserved for display port data. Even when using USB4 I still haven't seen an ssd case that can use all that bandwidth. Use case is video editing and maybe even egpu for Blender.
- bzzzt 2y ago
  I don't think bandwidth is reserved. Thunderbolt3/USB4 is a 40Gbit link which can also carry display data. The USB-C stuff with dedicated lanes for Displayport is ignored then. There's no EGPU support on the M series, but even if you could you can just use the GPU output so the entire Thunderbolt bandwidth is dedicated to the PCI-E card.
  - pier25 2y ago
    > I don't think bandwidth is reserved It is reserved. "Thunderbolt 4 has a maximum bandwidth of 40 Gb/s. However, this is a bit misleading because not all of that bandwidth can be used for data transfer. Approximately 8 Gbp/s can only be used for video, leaving 32 Gb/s for non-video data (PCIe 3.0: 4 lanes x 8 Gb/s). Further accounting for PCIe 8b/10b encoding and TB4's own overhead, you arrive at a peak data throughput of approximately 22 Gb/s. Not 40 Gb/s but not slow either." Source: https://tripplite.eaton.com/products/thunderbolt-4 https://tripplite.eaton.com/products/thunderbolt-4
    - deleted 2y ago
      [deleted]
- fulafel 2y ago
  One advantage of TB is that it's more like PCIe than USB, so you don't typically get the slowdown from adapter chips in things like USB SSD cases you mention.
  - pier25 2y ago
    In my experience USB4 cases typically go faster than TB4 cases. See this other comment of mine: https://news.ycombinator.com/item?id=41767470 https://news.ycombinator.com/item?id=41767470
fulafel 2y ago
All of networking, SSDs, eGPUs would go faster than that today, nevermind during the lifespan of the device or concurrent use of those. (Current SSDs and Ethernet seem to go at about 100 Gbit/s, GPU external buses are an order of magnitude up from there)

I'm very interested in your use case where 40Gbit/s is not more than enough.

by bzzzt 2y ago

I'm very interested in your use case where 40Gbit/s is not more than enough.

You don't really have 40gbits for data transfer in tb3/4. A good chunk is reserved for display port data. Even when using USB4 I still haven't seen an ssd case that can use all that bandwidth. Use case is video editing and maybe even egpu for Blender.

bzzzt 2y ago
I don't think bandwidth is reserved. Thunderbolt3/USB4 is a 40Gbit link which can also carry display data. The USB-C stuff with dedicated lanes for Displayport is ignored then. There's no EGPU support on the M series, but even if you could you can just use the GPU output so the entire Thunderbolt bandwidth is dedicated to the PCI-E card.
- pier25 2y ago
  > I don't think bandwidth is reserved It is reserved. "Thunderbolt 4 has a maximum bandwidth of 40 Gb/s. However, this is a bit misleading because not all of that bandwidth can be used for data transfer. Approximately 8 Gbp/s can only be used for video, leaving 32 Gb/s for non-video data (PCIe 3.0: 4 lanes x 8 Gb/s). Further accounting for PCIe 8b/10b encoding and TB4's own overhead, you arrive at a peak data throughput of approximately 22 Gb/s. Not 40 Gb/s but not slow either." Source: https://tripplite.eaton.com/products/thunderbolt-4 https://tripplite.eaton.com/products/thunderbolt-4
  - deleted 2y ago
    [deleted]
fulafel 2y ago
One advantage of TB is that it's more like PCIe than USB, so you don't typically get the slowdown from adapter chips in things like USB SSD cases you mention.
- pier25 2y ago
  In my experience USB4 cases typically go faster than TB4 cases. See this other comment of mine: https://news.ycombinator.com/item?id=41767470 https://news.ycombinator.com/item?id=41767470

fulafel 2y ago

All of networking, SSDs, eGPUs would go faster than that today, nevermind during the lifespan of the device or concurrent use of those. (Current SSDs and Ethernet seem to go at about 100 Gbit/s, GPU external buses are an order of magnitude up from there)