Review: Promise's $249 TD-300 Thunderbolt 3 Dock Offers Lots of USB Ports and an SD Card Reader

Discussion in 'Guides, How Tos and Reviews' started by MacRumors, Jan 26, 2018.

  1. MacRumors macrumors bot


    Apr 12, 2001

    Thunderbolt 3 docks continue to hit the market, and today we're taking a look a recent entrant from popular data storage company Promise Technology, the TD-300 Thunderbolt 3 Dock.


    I've tested quite a few Thunderbolt 3 docks over the past year, and the TD-300 ranks right up with the best I've seen due to standout features like five USB 3.0 ports and an SD 3.0 card reader. At $249, it's also priced very competitively against other full-featured Thunderbolt 3 docks.


    In the box, you'll find the typical contents for a dock of this type, including the dock itself, an external power brick, and a 0.5-meter Thunderbolt 3 cable. Any other cables such as for USB devices or an HDMI display need to be provided separately, although they frequently come with the devices you'd be connecting.

    The TD-300 comes in a horizontal form factor similar to many others on the market, and it sits nicely under an external display. It measures just over 9 inches wide, 3.5 inches deep and a little over an inch tall, and weighs just about a pound, so it's a pretty typical Thunderbolt 3 dock from a size perspective.


    The enclosure is made of black plastic, matte on the top and glossy around the sides, which sets it apart from the silver and gray finishes seen on most of the other docks I've tested. There's a fairly small Promise Technology logo in the rear left corner of the dock's top, but it's not terribly obtrusive, and the top tapers slightly toward the front of the dock.


    The front of the dock includes a pair of status lights, a green one letting you know there's power to the dock and a blue one signifying an active connection to a computer. The lights are fairly bright and can be distracting in a dark room. You'll also find the handy SD card slot, a pair of USB Type-A 3.0 ports (the left of which supports higher-power 5W/1.5A charging) and an audio in/out port.


    On the rear, you'll find three more USB Type-A 3.0 ports, a Gigabit Ethernet port, two Thunderbolt 3 ports, an HDMI 2.0 port, and the DC-in connection for power.

    USB Ports

    With all five USB ports being USB 3.0, they support 5 Gbps connections, which isn't the fastest standard but is typical for Thunderbolt 3 docks where bandwidth is frequently shared among a host of peripherals. Most other docks on the market offer only three USB ports, so the inclusion of five here offers some nice expandability, and with two of them on the front there's easy access for USB accessories that only need to be attached occasionally.

    Testing transfer speeds using a 10 Gbps USB 3.1 Gen 2 CalDigit Tuff external SSD and Blackmagic's disk speed testing software, I saw speeds around 350 MB/s read and 320 MB/s write through the Type-A USB 3.0 ports, which is typical for docks like this.

    USB-A CalDigit Tuff speeds

    If you want better transfer speeds and don't need the second Thunderbolt 3 port on the dock for a display, you can hook up a USB-C external drive that way, where I saw speeds in excess of 500 MB/s read and 475 MB/s write with the CalDigit Tuff.

    USB-C CalDigit Tuff speeds over Thunderbolt 3 port​

    With a top-of-the-line Thunderbolt 3 drive like the new ThunderBlade V4 from OWC, I saw read and write speeds approaching 1900 MB/s, pretty close to what I previously saw with a direct connection to my MacBook Pro. Obviously if you start tacking other high-bandwidth peripherals like a 4K HDMI display on to other ports on the dock, the SSD speeds will drop.

    SD Card Slot

    The TD-300's SD 3.0 card reader on the front of the dock is a great feature that's missing on most other Thunderbolt 3 docks released so far. If you've got photos or other data stored on an SD card, it's great to be able to just pop the card into the front of the dock and have it show up on your computer without needing to connect a separate card reader over USB.


    In line with other Thunderbolt 3 docks, Promise's dock can support either a single 5K display attached to the downstream Thunderbolt 3 port, or a pair of 4K displays attached through the Thunderbolt 3 port and the HDMI port. I tested extensively with an LG UltraFine 5K display hooked up via Thunderbolt 3 and it ran at the full 60 Hz refresh rate with no problems. The usual macOS System Preferences let you manage the monitors in terms of mirroring/extending and arrangement.


    The TD-300 offers up to 60 watts of charging power over its Thunderbolt 3 connection to a computer, which is enough for a 13-inch MacBook Pro but falls short of what a 15-inch model might be able to draw at maximum load. In reality, 60 watts is often enough to keep even a 15-inch MacBook Pro charged up under normal use, but if you're doing a lot of heavy lifting with your machine it might not be able to quite keep up. Recharging a depleted battery via the TD-300 will also be a bit slower than from an 85-watt dock or the 87-watt power adapter that comes with the MacBook Pro.

    Most Thunderbolt 3 docks seem to be going with the 60-watt power delivery, so the TD-300 is by no means unique in this limitation, but there are 85-watt ones on the market if that's a necessity for you.


    The Promise TD-300 Thunderbolt 3 Dock offers a solid set of features at a very competitive price point compared to similar docks. It doesn't have FireWire or eSATA ports like a few competitors have, but with those ports becoming less and less popular it makes sense for Promise to put its focus on the flexibility of USB while also including a built-in SD card reader.

    Full 85-watt charging support would have been nice to see, so if you're a 15-inch MacBook Pro owner you'll need to decide if that's a dealbreaker based on whether you push your machine hard enough to need the full power, and if so, whether you're okay with using the standard MacBook Pro power adapter alongside the dock.

    But overall, the TD-300 stacks up very well against the competition and is worth a close look. The Promise TD-300 is priced at $249 and is available from a variety of retailers including B&H Photo and Amazon.

    Note: Promise Technology provided the TD-300 to MacRumors free of charge for the purposes of this review. No other compensation was received. MacRumors is an affiliate partner with B&H Photo and Amazon and may earn commissions on purchases made through links in this article.

    Article Link: Review: Promise's $249 TD-300 Thunderbolt 3 Dock Offers Lots of USB Ports and an SD Card Reader
  2. Appleaker macrumors 68020

    Jun 13, 2016
    Nice to see adapters are still outrageously priced.

    Sounds like an okay product but not at that price.
  3. camelia macrumors 6502


    Apr 3, 2015
    Mexico City
    It looks nice, but very expensive for me :oops:
  4. riclf macrumors newbie


    Mar 26, 2014
    San Francisco
    I like it. I won't pay that money for a set of ports! Its outrageous. I guess First-To-Market are trying to see what the market will pay. NOT THIS!
  5. -Garry- macrumors 6502a


    Oct 23, 2005
    Manchester, UK
    This might be the dock for me. I’m currently using an LG 27UD88 connected via USB-C and a £40 HooToo docking station also connected via USB-C.

    I’ve been waiting for a dock that allows me to use all my peripherals without a performance deficit with a single cable... oh and an SD card reader. Originally I specifically wanted one that provides 87W of power for my MacBook but I’ve found that 60W charges it just fine, and I’m quite a heavy user of Premiere and Lightroom.

    I’m guessing I could connect the monitor to the dock with HDMI, connect my SSD to the dock with USB-C and have the other ports available for peripherals? If so, that’d be great.
  6. riclf macrumors newbie


    Mar 26, 2014
    San Francisco

    Good point on the HDMI. I run 3 screens. Wish there were more HDMI ports on that adapter.
  7. djbuddha macrumors 6502


    Aug 7, 2011
    I have the same monitor connected to and OWC Thunderbolt 3 dock on my 2017 rMBP w/ touchbar.

    The only issue I have with it is when I turn the monitor off. I like to run some video encodes with the monitor off and it does complete... but the computer goes into this weird hybrid sleep mode where SOME things don't work. Then when I turn the monitor back on, I have to open the lid and close it again. Not sure if it's dock related (I should try this with the monitor connected directly).

    Other than that anomaly I LOVE the OWC dock.
  8. bernuli macrumors 6502a

    Oct 10, 2011
    That might be due to the computer reverting back to on board video processing vs using the graphics card when the monitor goes offline. Perhaps try disabling "automatic graphics switching" and see if you get more consistent results.
  9. foobarbaz macrumors 6502a

    Nov 29, 2007
    Oh man, literally every TB dock has one killer drawback for me. In this case it's the lack of 80W charging. Otherwise it would have been perfect for me.

    I absolutely cannot recommend this for a 15 inch.

    To rephrase the quote: A 60W power supply means that your battery will *loose* charge during intensive tasks even though it's plugged in. Not only is that a terrible experience if you actually want a fully charged laptop at points during the work day, it will also wear down the battery faster with meaningless cycles.

    Especially when spending this much money, you don't want that as a permanent compromise.
  10. AzureCoast macrumors newbie


    Jan 2, 2018
    San Francisco - Côte d'Azur
    The MacBook Air with a retina screen and TouchID would be worth an upgrade and no usb3 desired. Would be happy to have MagSafe vs the pityful detachable cable stuff the new MacBook Pro has.
  11. djbuddha macrumors 6502


    Aug 7, 2011
    I read this everywhere ....

    I have a max spec 2017 15" MacBook Pro and I spend a lot of time (probably 70% of the time) exporting Prores 4444 video through Final Cut X.

    My battery remains at 100 always through my OWC dock at 60 watts.

    It's been the same behaviour since September. My CPU AND GPU usage are through the roof during these processes. (As seen with istatmenu).

    Also, I've seen my MacBook charge from 20% to 100 while doing these processes. So again, not sure why this is a rumour.
  12. MrX8503 macrumors 68020

    Sep 19, 2010
    SD card slot, displayport, USB3 type A, ethernet, thunderbolt 2, and 100w.

    That's my dream dock, but I don't think that's what the majority of people want.
  13. SecuritySteve macrumors 6502a


    Jul 6, 2017
    Where do you get that space grey Apple coffee mug... ?
  14. Menneisyys2 macrumors 603

    Jun 7, 2011
    Another 60 watt one? Thanks but no thanks.
    --- Post Merged, Jan 26, 2018 ---
    Do you use it with an external (preferably 4k+) monitor? If you do, this will add another +10Watts of power.

    And if, for some reason, you start copying something from a USB CD/DVD-ROM, you'll over 87W of power. (This is my experience: with full CPU & GPU use (e.g., XCOM 2), with an additional DVD-ROM copying in the background, not even the 87W factory charger is sufficient.)
  15. Jimmy James macrumors 601

    Jimmy James

    Oct 26, 2008
    It seems like ports in a box should be $49. I wonder what the licensing fees are.
  16. VictorTango777, Jan 26, 2018
    Last edited: Jan 26, 2018

    VictorTango777 macrumors 6502

    Oct 28, 2017
    Tell Apple to provide proper support for DisplayPort MST daisy chaining and MST hubs instead of trying to force people to buy Thunderbolt monitors.
    --- Post Merged, Jan 26, 2018 ---
    I think that Apple is partly to blame for this situation. Instead of including the same USB-C power adapter with all the MacBooks and MacBook Pro touchbar laptops, they include a different power adapter for each of these. The dock manufacturers probably test only the 13 inch MacBook Pro because it is the cheapest for them to buy. Since the 13 inch MacBook Pro includes a 60 watt power adapter, these companies decide to support only 60 watt charging. If Apple included the same power adapter with all Thunderbolt 3 Mac laptops, the situation might be different.
  17. djbuddha macrumors 6502


    Aug 7, 2011
    Using a 27" LG 4K USB-C monitor (27UD88) on my mac, it's fine.
  18. jamisonbaines macrumors regular

    Dec 14, 2007
    You must really love USB2.

    I'm fine with USB-C charging but I would like the SD card slot to return. My ideal port config would be TB3 and headphone jack on the left, TB3 and an SD card reader on the right. Minimal but with the option to add a dongle/hub to either side as required. But I'm not buying until we get a quad core 13" with decent graphics.

    Oh and this dock costs way too much.
  19. Populus macrumors 6502a


    Aug 24, 2012
    Valencia, Spain.
    And yet, as always, only one thunderbolt 3 in and one out. No more USB-C on this type of device... I wonder why. Is this how we supposedly have to buy USB-C or thunderbolt 3 devices? We have no ports!
  20. djbuddha macrumors 6502


    Aug 7, 2011
    The reason for 1 in and 1 out is because you approach the data limit of Thunderbolt 3. If add another Thunderbolt 3 port, you'd see a huge performance dip across the other ports on the dock.
  21. Populus macrumors 6502a


    Aug 24, 2012
    Valencia, Spain.
    So why there are USB-A hubs and there are not USB-C hubs? I don't understand... If I make the transition to all USB-C, then I'm stuck with the 2 ports of the MacBook pro?
  22. springsup macrumors 65816


    Feb 14, 2013
    Like with the other TB3 docks, it's just not worth that amount of money. I'd rather keep my less-integrated, dongle-based solution and not be $250 poorer. That's almost the cost of a new, latest-gen Apple Watch.
  23. manu chao macrumors 603

    Jul 30, 2003
    You cannot branch any of the non-standard-USB features of USB-C (ie, all the alternate modes). A USB-C hub would essentially only offer standard USB 3 capabilities that a USB 3 A-type plug has (maybe 3.1 gen 2, ie, 10 Gbit/s and higher power delivery to peripherals) with the USB-C plug shape. Equally, power delivery to the computer would probably only work via one of the USB-C ports (as it does in the existing USB-C hubs). Note that none of the TB docks (from TB1 through TB3) ever offered branched TB ports, only pass-throughs.

    For standard USB devices (keyboard, mouse, storage, cameras, microphones, etc.) this would not be a problem but at the very least it'll be confusing that the ports on the USB-C hub behave differently than the USB-C ports on the computer. I don't know if more complex USB devices (eg, a USB to Ethernet adaptor) worked in the pre-USB-C days when connected to the computer via a USB hub.
  24. theluggage macrumors 68040

    Jul 29, 2011
    They are - they're called USB hubs, docks, or similar. They share the capabilities of a single USB port amongst several other ports. Even with USB-C, that consists of either (a) one 5Gbps USB-3 channel and 2 DisplayPort lanes (standard res only) or (b) 4 DisplayPort lanes (needed for 4k @ 60Hz, still no 5k) but leaving only one USB 2.0 channel.

    If you can live with those limitations then you don't need to fork out for a Thunderbolt 3 dock.

    A TB3 dock has two 20Gbps links to the host, carrying a flexible mix of PCIe and DisplayPort, and contains extra controllers for USB and Ethernet that act as though they were connected to the computer's PCIe bus. A TB3 hub can handle far more throughput than a cheaper USB-based device.

    (Side note - when people review these docks it would be great to run System Report or other diagnostics and figure out whether, e.g. all the USB 3 ports run directly from a controller, whether the ethernet controller is on PCIe or USB3 etc. I'm betting that the sound and SD slot are almost always on USB...)

    Because (a) implementing a mutifunction 'smart' port like USB-C is more difficult and expensive than implementing an old fangled USB-A port, and largely pointless because...

    (b) currently, people have lots of USB-A devices to connect and the majority of USB-C devices on the market are only USB3.1gen1 and don't gain anything from being connected via USB-A rather than C... Then, if you do have an actual 10Gbps device, its probably something performance-critical like a superfast NvME SSD or RAID array and you're probably going to want it connected directly to the host, not contending for other devices for bandwidth. Ditto for TB3 devices - plus, TB is a bus architecture designed to daisy-chain, rather than a hub-based "star" architecture like USB.

    Put simply, in early 2018 it makes more sense to get a hub with enough USB-A ports for your existing devices, and only worry about adapters for the few USB-C devices you have that you can't connected directly to the host (and if they're not sold by Apple they probably came with a C-to-A cable in the box - then there's all those double ended USB-C/USB-A flash drives).

    Come 2020, the balance may have changed - plus, hopefully, we'll have USB3.2 (two USB 3.1 channels per USB-C port) and DisplayPort 1.4/HDMI version whatever so you'll be able to mix 4k and USB 3 on the same port.
  25. zorinlynx macrumors 603


    May 31, 2007
    Florida, USA
    Does anyone know if these will work with a Thunderbolt 2 equipped Mac using Apple's adapter?

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31 January 26, 2018