CPU usage, USB vs. Thunderbolt

Discussion in 'Digital Audio' started by Ylan, May 31, 2018.

  1. Ylan, May 31, 2018
    Last edited: May 31, 2018

    Ylan macrumors member

    Ylan

    Joined:
    Oct 27, 2016
    Location:
    Stockholm
    #1
    Comrades,

    I have a Focusrite Scarlett 1st generation, and am bugged by the latency while tracking, so I am thinking of upgrading. I know that the 2nd generation Scarlett has considerably less latency, but am pondering digging deep in my pockets and go Clarett (Thunderbolt). Not just for the very small latency, but also for the preamps.

    Now I wonder whether anyone knows how much smaller the cpu cycle footprint of Thunderbolt really is than USB. Is it that much smaller that it is significant? I have a fairly decent iMac but it's definitely not impossible to max out a kernel.

    I can't seem to find any numbers or tests that include CPU usage.

    Humbly, Ylan
     
  2. 0009827 Suspended

    Joined:
    Jul 15, 2018
    #2
    Quoted:
    “Lower latencies in Thunderbolt can be indirectly attributed to a technology in it called Direct Memory Access (DMA): “This is a Thunderbolt peripheral’s ability to transfer data with the Mac’s memory directly without the intervention of the Mac’s CPU,” says Robindore. “Since the CPU isn’t required for the data transfer between peripheral and Mac, it’s freed up for things like plug-ins and processing.”

    With the CPU's load lightened, it can handle smaller buffer settings and thus lower latency.”

    Thunderbolt focusrites are fantastic as far as I have been told, I didn’t yet stump the cash to upgrade my Scarlett, but do plan to!
     
  3. Ylan thread starter macrumors member

    Ylan

    Joined:
    Oct 27, 2016
    Location:
    Stockholm
    #3
    Thank you!

    Humbly, Ylan
     
  4. Macalway, Aug 6, 2018
    Last edited: Aug 6, 2018

    Macalway macrumors 68030

    Joined:
    Aug 7, 2013
    #4
    I'm not so sure about the gen2 being much better with latency on a Mac. The trick it seems is with the new Windows drivers (OS X doesn't have drivers). Also, there are a number of posts about using the 2nd gen. drivers with 1st gen. Scarletts and getting the improvements seen with gen2. At least until Focusrite did something so you couldn't do that any more :D (which makes sense right?).

    I have both first and second gen and don't notice any improvements with Macs. Then again, i'm no expert.

    BTW, I also own a UAD Arrow TB3 interface. Now these things are way advanced. You really have to try these to get a grasp of it. The Arrow is good as it's cheap (enough for the average dabbler). Moving up things get way out of control, cost wise. TB is going to get you the best bandwidth and latency, but it depends on your usage. It might be overkill, with USB being perfectly adequate.
     
  5. Ylan thread starter macrumors member

    Ylan

    Joined:
    Oct 27, 2016
    Location:
    Stockholm
    #5
    I recently bought a second hand Clarett 4pre, and I get the feeling that my CPU meters in Logic Pro X indicate a slightly lower CPU load. Now this could be because of updates to Logic, so I can't say I'm sure it's because of my new Thunderbolt interface.

    I am however very happy with it. I played DI'ed bass with my kid today, she played DI'ed guitarr and sang, all in box with Amp Designer and Logic's effects. I couldn't notice any latency whatsoever. And it really sounds good to, and I believe it can drive any pair of headphones, which my previous interface (Focusrite Scarlet 2i2, gen 1) definitely couldn't.

    Humbly, Ylan
     
  6. brdeveloper macrumors 68020

    brdeveloper

    Joined:
    Apr 21, 2010
    Location:
    Brasil
    #6
    I bought an Apogee Element 46 with 4 preamps (It also has a two-preamp version, the Element 24). My Mac is an Early-2013 15" one with Thunderbolt 1 ports. Although the Element series is rated as Thunderbolt 2, it runs smooth on my Mac with latencies as low as one would expect from a TB interface. If you have a TB3 Mac, you'll need an adapter (TB3 to TB2) from Apple or perhaps other brands as Startech, Sonnet, etc.

    Don't know how it compares to USB interfaces (I had a pretty old M-Audio Fast Track Pro) in terms of CPU usage, but I'm able of recording with a dozen of tracks (~2-3 synths, 1 drummer and instruments/vocals) and automations. Not clicks yet at 48KHz/24-bit recording. Some day I'll try to reach its processing limit.
     
  7. Ylan thread starter macrumors member

    Ylan

    Joined:
    Oct 27, 2016
    Location:
    Stockholm
    #7
    Regarding bandwidth I doubt whether I'd ever outgrow even USB 2. It's the direct access to PCIe of Thunderbolt that makes the latency so much lower. And it's own controller hardware that makes it so much more expensive.

    I bought my Clarett 4pre second hand, and cable and adapter was included.

    I am very happy with it, but I might have been that with a more modern USB interface aswell. One reason that I went TB was that the headphone amps of the Claretts are a lot better and can drive any pair of headphones. An other was that I got a really good price.

    Having bought a TB interface I'm however still intellectually or technically interested in the CPU "cost" of USB. And have still not found anything about it.

    So if you know anything about this, or where one could find info about this, please answer.

    Cheers, Ylan
     

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