Suggestions to run 3 QHD 32" displays on a laptop

JadeMonkeyStang

Limp Gawd
Joined
Aug 7, 2001
Messages
497
Hey all, long time no [H].

I want to run three 32" Monitors (LG 32GK650F / 32GK850F) on my laptop at their native QHD 2560 x 1440 resolution. I've tried a couple of different docks / port replicators but so far nothing that can handle all 3 at this resolution, or even 2 of them. I'd love to find a dock that can handle all 3 at full resolution but one that can handle 2 would work as well as I can connect the third directly to the laptop via HDMI. My laptop has HDMI output, USB 3, and USB-C. Appreciate any recommendations!
 

Spun Ducky

Gawd
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Feb 1, 2009
Messages
638
Laptop model would help a lot. Even if the ports existed not all ports are made equal and also chipset support for higher resolutions.
 

jeremyshaw

[H]F Junkie
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Aug 26, 2009
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Are you looking to run them at 60Hz or their 144Hz ranges? HDR or no? With HDR, the bandwidth budget gets really tight.

Here are the numbers (usable bandwidth, after encoding, blanking, etc):
DP 1.2 (4 lanes) - 17.28Gbps
DP 1.3/DP1.4 (4 lanes) - 25.92Gbps
HDMI 1.4 - 8.16Gbps
HDMI 2.0 - 14.4Gbps

Each monitor needs:
1440p60 SDR ~5.63Gbps
1440p144 SDR ~14.08Gbps
1440p60 HDR ~7.04Gbps
1440p144 HDR ~17.60Gbps

If you have anything other than a decent AMD Ryzen laptop (some of the cheaper ones are limited to HDMI 1.4 - like my E485), Intel 10th gen, or an Nvidia laptop with the Nvidia dGPU attached directly to the HDMI (or potential USB-C DP Alt Mode), then you have DP 1.2 (at best) and potentially HDMI 2.0, though more likely 1.4.

You know what, without knowing your exact laptop model, there are too many contingencies. I'll echo Spun Ducky 's request above.
 

JadeMonkeyStang

Limp Gawd
Joined
Aug 7, 2001
Messages
497
Spun Ducky and jeremyshaw , you're both absolutely right, laptop model would definitely help; sorry for not including that. I'm using a Dell Latitude 7490 so nothing fancy. Also have an old Sager NP8658 / Clevo P650RG but I know that will be more of a struggle with no USB-C.

I'm fine with 60Hz and no HDR for the multiple setup, will be using it 95% for productivity and streaming video on one of the monitors. Really just looking for full rez for cleaner text / spreadsheets and more real estate across the 3 monitors.

An external video card / eGPU would also be something I could do but I know next to nothing about those setups. Been out of the PC world for years and the amount of changes is a little daunting. Really appreciate you help.
 

jeremyshaw

[H]F Junkie
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Messages
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Ah, I see. Latitude 7490 - USB-C does support DP-Alt Mode, but only DP1.2 and HDMI 1.4.

With that in mind, I cannot think of a dock that would good-naturedly, smartly split that one DP 1.2 signal into 3 1440p60 signals, and most modern docks will halve the DP bandwidth (taking 2 of the 4 lanes), in favor of an USB 3.0 data pair (which allows for GbE, faster USB, etc). With half of the bandwidth, even two 1440p60 SDR monitors becomes out of reach.

That being said... there is one last moonshot. Does your 7490 have Thunderbolt 3? If it does, we're still in business! But the docks get pricier. Dell's WD19TB dock claims to be capable of taking a TB3 link (driven by the 7490's DP 1.2) to 3 1440p60 SDR displays. That being said, TB3 is a bit buggier in my experience (maybe others will have better experience?).

Though with TB3, one could also get a small external GPU dock, like I did. I have more familiarity with Nvidia, so I chose a Nvidia eGPU dock, and that thing's only limit was the Nvidia GPU's output limit (4 DP1.4 streams in theory, though my dock/eGPU only had two DP 1.4 connections and one HDMI 2.0 connection).
 
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DoubleTap

2[H]4U
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Dec 16, 2010
Messages
2,479
I had the exact same issue with my work laptop about a year and a half ago.

This absolutely did the trick and performance for office work was great - I never noticed which screens were USB vs HDMI (although I never watched videos...)


https://www.amazon.com/gp/product/B075HMWLJF/
Plugable USB 3.0 Dual 4K HDMI 2.0 Adapter with Gigabit Ethernet for Windows (Supports Two HDMI Displays up to 3840x2160@60Hz, Windows 10, 8.1 & 7)


1581450157817.png
 

JadeMonkeyStang

Limp Gawd
Joined
Aug 7, 2001
Messages
497
That being said... there is one last moonshot. Does your 7490 have Thunderbolt 3? If it does, we're still in business! But the docks get pricier. Dell's WD19TB dock claims to be capable of taking a TB3 link (driven by the 7490's DP 1.2) to 3 1440p60 SDR displays. That being said, TB3 is a bit buggier in my experience (maybe others will have better experience?).

Though with TB3, one could also get a small external GPU dock, like I did. I have more familiarity with Nvidia, so I chose a Nvidia eGPU dock, and that thing's only limit was the Nvidia GPU's output limit (4 DP1.4 streams in theory, though my dock/eGPU only had two DP 1.4 connections and one HDMI 2.0 connection).
Unfortunately no TB3 on my version of the Latitude 7490, that would have been awesome. Thanks for all the help!

Out of curiosity, which eGPU dock did you go with?
 

JadeMonkeyStang

Limp Gawd
Joined
Aug 7, 2001
Messages
497
I had the exact same issue with my work laptop about a year and a half ago.

This absolutely did the trick and performance for office work was great - I never noticed which screens were USB vs HDMI (although I never watched videos...)


https://www.amazon.com/gp/product/B075HMWLJF/
Plugable USB 3.0 Dual 4K HDMI 2.0 Adapter with Gigabit Ethernet for Windows (Supports Two HDMI Displays up to 3840x2160@60Hz, Windows 10, 8.1 & 7)


View attachment 222643
Thanks for the suggestion. Looks like this could work for both of my laptops. I'm going to give it a shot, appreciate it!
 

jeremyshaw

[H]F Junkie
Joined
Aug 26, 2009
Messages
12,350
Unfortunately no TB3 on my version of the Latitude 7490, that would have been awesome. Thanks for all the help!

Out of curiosity, which eGPU dock did you go with?
Lenovo's GTX1050 dock. Primary reason was its small size. I had a fantasy of bringing it with me on the go. Reality was quite disappointing.
 

JadeMonkeyStang

Limp Gawd
Joined
Aug 7, 2001
Messages
497
Lenovo's GTX1050 dock. Primary reason was its small size. I had a fantasy of bringing it with me on the go. Reality was quite disappointing.
I had the same fantasy but realize I probably wouldn't travel with it anyway. I'm usually hard pressed enough to bring the dock for my Nintendo Switch.
 

JadeMonkeyStang

Limp Gawd
Joined
Aug 7, 2001
Messages
497
I had the exact same issue with my work laptop about a year and a half ago.

This absolutely did the trick and performance for office work was great - I never noticed which screens were USB vs HDMI (although I never watched videos...)


https://www.amazon.com/gp/product/B075HMWLJF/
Plugable USB 3.0 Dual 4K HDMI 2.0 Adapter with Gigabit Ethernet for Windows (Supports Two HDMI Displays up to 3840x2160@60Hz, Windows 10, 8.1 & 7)


View attachment 222643
Wanted to say thanks DoubleTap! I have the Plugable adapter you linked for me sitting on my desk now and it's working great so far. Really appreciate you letting me know that it exists as it's doing exactly what I need. Have all three 32" displays setup and running great at native resolution, 2 via the Plugable USB to HDMI adapter and one plugged into my laptop via HDMI. Thanks so much for the recommendation.

Also lots of thanks to jeremyshaw for your help working through the issue and figuring out what my options were. Appreciate it!
 

DoubleTap

2[H]4U
Joined
Dec 16, 2010
Messages
2,479
Wanted to say thanks DoubleTap! I have the Plugable adapter you linked for me sitting on my desk now and it's working great so far. Really appreciate you letting me know that it exists as it's doing exactly what I need. Have all three 32" displays setup and running great at native resolution, 2 via the Plugable USB to HDMI adapter and one plugged into my laptop via HDMI. Thanks so much for the recommendation.

Also lots of thanks to jeremyshaw for your help working through the issue and figuring out what my options were. Appreciate it!
I'm glad it's working for you - if I had half a braincell of self interest, I would have tried to sell you mine - my new work laptop came with one of those USB C docks with dozen connections (including 3 video ports) so mine is just sitting around lol. Even without the new dock, I ditched my multi monitor rig for a big 38"...
 
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