LG UltraFine 5K - Hub speed tests (external disks)

[iBrooker]

Inspired by @Weaselboy's posts, I thought it would be cool to have a dedicated thread for speed tests via the monitors hub. Please post yours here!

Also see:

LG UltraFine 5K - Owners Thread

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Here are my quick tests, interestingly they vary depending on which adapter I use!

I am using a 128GB Crucial® m4SATA6Gb/s2.5-inchSSD (500GB/s read 175GB/s write) it's a few years old now but the only external SSD I have at present.

• This cheap USB-C adapter promises speeds up to 10Gbps gives me somewhat mediocre performance:

Connected directly to Mac - 183 MB/s write and 241 MB/s read
Connected via the monitor - 161 MB/s write and 232 MB/s read​

• This one from Sabrent which also promises speeds of up to 10Gbps gives me much better performance:

Connected directly to Mac - 189 MB/s write and 501 MB/s read
Connected via the monitor - 189 MB/s write and 348 MB/s read
​

I think I will be keeping the Sabrent

 

[sidewinder]

I have a LaCie "Porsche Design" 4GB bus powered HDD which has a USB 3.1 Gen. 1 interface (5 Gb/s) using a USB-C connector. It comes with a USB-C to USB-C and a USB-C to USB-A cables. For this test, I used only the USB-C to USB-C cable.

Connected directly to Mac - 124 MB/s write and 120 MB/s read
Connected via the monitor - 113 MB/s write and 114 MB/s read

 

[slaWter]

Good to see a dedicated thread for this. I also meant to pick up on that post.

Apparently, the USB-C hub is not able to deliver the full Gen. 1 speeds. That is really disappointing since it's only USB 3.0 speeds after all.

It's probably best to use a dedicated USB hub for faster USB-based external storage, especially for video related tasks.

I intent to use the integrated hub on one screen for my normal/slower USB peripherals (additional USB 3.0 hub, 8TB external HDD, 2 Time Machine HDDs, MM1 speakers and other small devices). It should still be quick enough for that.
The other screen's hub would be for faster stuff like USB-C to Ethernet (still ok with these speeds), card readers and also fast (Gen. 1) external SSDs for Lightroom and Bootcamp.
And that might not be the best idea. I'll have to try it. I rarely have sustained read/write speeds for photo/Lightroom work except when copying but hopefully it's still fast enough. And since each RAW photo is around 85MB it shouldn't slow things down that much. Still, not ideal. I really expected normal USB 3.0 speeds. Due to the longer cables, a small decrease in performance is acceptable but not this much!

 

[Weaselboy]

Here is my test from the other thread.

One surprising test I did though. I have a Samsung EVO 850 SSD in this Inatech USB3 enclosure I use for CCC clones. With the drive attached directly to the MBP, using Blackmagic, I get 390W/400R. The same test with the drive attached to a USB-C port on the LG I get 240W/320R. So the predictions that the TB3 bus would be saturated and drop these ports to USB2 speeds were incorrect. It is a little slower than the direct connection to the MacBook, but around 4X faster than the theoretical 60MBps speeds of USB2.

 

[dwdrummer959]

Here's some more data fwiw...

Software: Blackmagic Disk Speed Test V3.0
Computer: 2016 15" MBP 2.9Ghz 16GB RAM 1TB SSD Radeon Pro 460
Drive A: 500GB Samsung T3 SSD
Drive B: 250GB Samsung T3 SSD
Both drives were connected to the computer and then the 5K via the included USB-C to USB-A cable and then the Apple USB-A to USB-C dongle (I don't have any USB-C to USB-C cables)

A: Plugged in to a LEFT TB3 port, write was 396.5 MB/s read was 403.7 MB/s
A: Plugged in to LG UF 5K monitor, write was 227.2 MB/s read was 292.8 MB/s

B: Plugged in to a RIGHT TB3 port, write was 400.6 MB/s read was 426.2 MB/s
B: Plugged in to LG UF 5K monitor, write was 254.2 MB/s read was 342.6 MB/s

 

[slaWter]

Thanks a lot for providing these results dwdrummer959! Similar scenario to what I'd be using (also multiple T3 drives).
Quite disappointing to see such a big drop off to be honest.

EDIT:
It would be interesting to see what happens if you don't send a video stream to the display.
Can someone please test this:

-Connect a fast USB 3.0 SSD (400MB/s) to the USB-C hub on the 5K.
-Disable video output to the monitor (use only the MBP screen).
-Test the read/write performance of the SSD.

Those additional 5 Gbit/s shouldn't saturate TB3 next to the 5K stream. Maybe they use a low quality hub or doctored something with the speaker/webcam integration.

 

[slaWter]

It would be interesting to see what happens if you don't send a video stream to the display.
Can someone please test this:

-Connect a fast USB 3.0 SSD (400MB/s) to the USB-C hub on the 5K.
-Disable video output to the monitor (use only the MBP screen).
-Test the read/write performance of the SSD.

Those additional 5 Gbit/s shouldn't saturate TB3 next to the 5K stream. Maybe they use a low quality hub or doctored something with the speaker/webcam integration.

Bump for my request above. Can anyone please test this? Thanks.

 

[dwdrummer959]

Bump for my request above. Can anyone please test this? Thanks.

How do you disable the 5k screen when it's plugged in?

 

[slaWter]

How do you disable the 5k screen when it's plugged in?

SwitchResX has an option to enable/disable screens. I don't remember if macOS itself has it as well.

 

[Outrigger]

SwitchResX has an option to enable/disable screens. I don't remember if macOS itself has it as well.

it doesnt. and even if it does, no one is going disable the 5k screen and use it as a hub for harddrives since that would defeat the purpose of having a 5k screen.

 

[slaWter]

it doesnt. and even if it does, no one is going disable the 5k screen and use it as a hub for harddrives since that would defeat the purpose of having a 5k screen.

It would just be a test to see if the hub itself or the internal USB implementation is too slow or if for some reason the 5K stream saturates the TB3 link, which it shouldn't.
It would obviously just be a temporary setting for this test.

 

[maxb]

Just received my display today, yeah

one bug I have, the usb hub can't keep up with usb 3 speed, I connected a usb-c 3 to giga ethernet adapter to hit and I don't get more then 440mbps, I get full speed directly connected to the Macbook Pro... I'm I alone?

 

[inmotionnow]

Connected to MBP directly (left TB3 port):

• Seagate Backup Plus via Monoprice Palette Series 3.0 USB-C to USB Micro B Cable: 95.6 MB/s write, 97.2 MB/s read
• Crucial BX100 SSD in Orico USB 3.1 enclosure via Belkin TB3 Cable: 427.6 MB/s write, 504.1 MB/s read

Connected to UF 5K:

• Seagate Backup Plus via Monoprice Palette Series 3.0 USB-C to USB Micro B Cable: 95.1 MB/s write (0.5% reduction), 97.1 MB/s read (0.1% reduction)
• Crucial BX100 SSD in Orico USB 3.1 enclosure via Belkin TB3 Cable: 251.4 MB/s write (41% reduction), 347.7 MB/s read (31% reduction)

Looks like I'm getting full speed via the UF 5K with the slower Seagate drive but am taking a significant hit with the SSD.

 

[Dukat]

Software: Blackmagic
Computer: 2016 15" MBP 2.9Ghz 16GB RAM 1TB SSD Radeon Pro 460
Drive: Samsung T3 SSD (1TB)

Connected to MBP directly (15", right side port):

• Read: 434 MB/s
• Write: 417 MB/s

Connected to LG 5K:

• Read: 347 MB/s (20% reduction)
• Write: 255 MB/s (39% reduction)

 

[jeme]

So I just purchased this monitor - I am having the same issues with a gigabit Ethernet adapter connected to the monitor - using the Belkin Gigabit USB C Ethernet adapter. Has anyone solved these issues? Thanks

 

[wowee]

Hi. Just picked up this Monitor and am on the fence about keeping it. I am using a Macbook 12inch 2017 which works totally fine with this monitor BUT i am wondering if there is ANY WAY to reduce the HZ so I can get USB 3 speeds from the hub. I know other monitors have this option to switch from 4K 60HZ USB 2 Speed to 4K 30HZ with USB 3 speed.

Does any one know if this is possible??

thanks!

 

[jjd]

Hi. Just picked up this Monitor and am on the fence about keeping it. I am using a Macbook 12inch 2017 which works totally fine with this monitor BUT i am wondering if there is ANY WAY to reduce the HZ so I can get USB 3 speeds from the hub. I know other monitors have this option to switch from 4K 60HZ USB 2 Speed to 4K 30HZ with USB 3 speed.

Does any one know if this is possible??

thanks!

Yeah. I just got one to use with my 14" MBP. I have a Logitech 1080p webcam plugged into the "hub" on the back (coz the built in cam is not good) but it can't even handle that. Makes Zoom and Teams calls unusable. In fact, even if I switch back to the built in camera in the LG but leave the Logo cam plugged in, it makes the video and audio unusably choppy. Hopeless.