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How to get max refresh rate at 3840×1600 from a Dell Latitude 5310?

Updated on 24-08-2023 in Docking Station
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13 on 14-02-2023

Hi, I want to connect an LG 38GN950 monitor (https://www.lg.com/us/monitors/lg-38gn950-b-gaming-monitor) to a Dell Latitude 5310 laptop (https://www.dell.com/support/manuals/en-us/latitude-13-5310-2-in-1-laptop/lati_5310_2_in_1_setupspecs/ports-and-connectors?guid=guid-bf77d3d3-74dc-46f0-9288-a41e578b290e). The monitor’s max resolution is 3840×1600@144. The laptop has an HDMI 1.4 port, but according to specs also supports DisplayPort 1.2 over USB Type-C in Alt Mode. The USB socket has the flash icon (https://www.club-3d.com/en/technology/15/usb_c_over_alt_mode/) so Alt Mode should be supported.

As HDMI 1.4 only supports 4K at 30Hz (https://en.wikipedia.org/wiki/HDMI#Version_1.4) I only get 30Hz when using the latop’s native HDMI port. But of course I would like to get as high a refresh rate as possible. So I thought using DisplayPort 1.2 over USB Type-C in Alt Mode should manage up to 60Hz even in 3840×1600 (https://en.wikipedia.org/wiki/DisplayPort#1.2).

I got this (probably low quality) LogiLink adapter, which claims to support 4K@60: https://www.reichelt.com/de/en/usb-3-0-adapter-usb-c-hdmi-usb-a-usb-c-4k-60hz-aluminum-logilink-ua0390-p337093.html but I only got 30Hz for every resolution above 1080p on the Latitude laptop. I then tried it on an Dell Precision 7760 (https://www.dell.com/support/manuals/en-us/precision-17-7760-laptop/precision_7760_specs/external-ports?guid=guid-a1a8875e-b8bc-4c43-9e7b-97f30705ba6) where I got up to 60Hz. So I am wondering what prevented 60Hz on the Latitude 5310 and if another adapter like the Club 3D CSV-1534 (https://www.club-3d.com/en/detail/2386/usb_type_c_to_hdmit_2.0_usb_2.0_usb_type_c_charging_mini_dock/) would enable it?

Furthermore, this LogiLink adapter had a problem on both laptops: namely that it only seemed to support 16:9 resolutions. The LG 38GN950 always had black stripes on both sides for every resolution. For 21:9 resolutions there were even black stripes on the top and botton, too. I hope this is nothing the CSV-1534 would have.

So how would I get the maximum refresh rate (at least 60Hz) at 3840×1600 out of the Latitude? Should the CSV-1534 be able to do it or is there a limitation with the laptop preventing it? Any thoughts? Thanks!

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Baak 0 on 15-02-2023

The latitude has DP 1.2 this has a bandwidth of max 21.6 Gbps.

The resolution (at 8 bits) of 3840 x 1600 @144Hz requires 26.54 Gbps

@120Hz = 22.12Gbps

@100Hz = 18.43Gbps

The LogiLink should be able to give you 4K60Hz, makes me think that your HDMI cable is not HDMI 2.0.

You might want to get a direct cable like,

https://www.club-3d.com/en/detail/2352/usb_3.1_type_c_cable_to_displayport_1.2_uhd_adapter_m-m_1.2m-3.94ft/

 

 

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Gabriel 0 on 15-02-2023

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Gabriel 0 on 15-02-2023

Thanks for your reply! 🙂

I used the HDMI cable provided with the LG 38GN950 so I would think it supports up to 3840×1600 10bit at 75Hz (as stated in the monitor specs). Also the same cable got me 60 Hz with the LogiLink adapter on the Dell Precision 7760 laptop. So I guess the cable can be ruled out?

The direct cable you suggested is USB-C to DisplayPort. Would there also be an equivalent for USB-C to HDMI? Or should I get an extra DisplayPort to HDMI adapter?

The thing is that the monitor’s only DisplayPort socket is already taken by my other PC. That’s why I thought I could use HDMI for the Dell Latitude Laptop. Or could you recommend a good DisplayPort KVM switch I could use to switch between two DisplayPort signals?

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Baak 1 on 15-02-2023

3840×1600 10bit at 75Hz= 16.59 Gbps (within HDMI 2.0 or DP1.2 specs)

For HDMI this would be what you need

https://www.club-3d.com/en/detail/2424/usb_c_to_hdmi_2.0_uhd_cable_active_m-m_1.8m-5.91ft/

The Precision is in a league of it’s own, every port on that device is at least 1 generation up from the Latitude.

I would not invest into a KVM if the Latitude is not up to par with your other equipment. But there are DisplayPort solutions.

https://www.club-3d.com/en/detail/2595/displayport-hdmi_kvm_switch_for_dual_displayport_4k_60hz/

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Gabriel 2 on 15-02-2023

All right. Thanks for the link! I agree that KVM is over the top for my needs. 🙂

I suppose I could give the CAC-1514 cable a try. This would rule out that the problem is with my HDMI cable. But maybe the LogiLink adapter is just trash to begin with?

I would have liked the CSV-1534 for its extra USB-C socket, because the Latitued only has one. Or could anything go wrong when I use the CAC-1514 cable over an USB-C hub, so I got extra USB-C sockets from there?

Baak on 15-02-2023

The extra USB-C will take bandwidth of the displays resolution. I think there is the problem.

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Gabriel on 15-02-2023

Hm, the USB-C port taking bandwidth? Do you expect this to be an issue of the CSV-1534 as well? I think, I will take my chances with the CSV-1534. Its price is 3 times that of the LogiLink so this must be good for something, I hope. If I still cannot get 60Hz with the CSV-1534, I will try the CAC-1514 cable next.

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Gabriel 2 on 22-03-2023

I now got the CAC-1588 which is supposed to be capable of 4K at 120Hz. So the adapter can no longer be the problem. The HDMI cable I use can do at least 75Hz at 3840×1600 as I tested it on another PC.

But I still only get 3840×1600 8-bit at 30Hz out of the Dell Latitude 5310. So I guess it is not really “DisplayPort 1.2 over USB Type-C in Alt Mode”? Because DisplayPort 1.2 should be able to do 60Hz in 3840×1600, right?

Baak on 22-03-2023

I can only think that the Dell is not doing what it should from it’s USB-C port.

Have you completely updated the Firmware and BIOS of the Dell? Other that this advice, I’d start asking Dell why the port doesn’t support what you need and what Dell claims what it should do.

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Gabriel on 22-03-2023

Yeah, the firmware is up to date. Hope it will work with my next laptop…

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joevt 1 on 03-04-2023

The Flash icon is a Thunderbolt icon.

The Logilink adapter cannot output 4K60 from DisplayPort 1.2 because it is a USB-C adapter that uses two of the 4 super speed lanes for USB 3.0. The remaining 2 lanes for HBR2 is limited to 8.64 Gbps which is enough for 360MHz 8bpc. That’s enough for 4K30 HDMI. For 4K60 you would need 4:2:0 but I don’t think DisplayPort supports 4:2:0.

Maybe the Logilink adapter supports 2 lanes of HBR3 (up to 12.96 Gbps) using DisplayPort 1.4. But that won’t help since the Dell Latitude 5310 is limited to DisplayPort 1.2. But even with HBR3, you would be limited to 540MHz 8bpc which is enough for 4K60 CVT-RB timing but not HDMI timing. You would need 4:2:2 (16/24 components) or 4:2:0 (12:24 components) or 6bpc to get HDMI timing. Perhaps your display does not require HDMI timing (3840 x 1600 is not a CTA-861 mode). The Dell Precision 7760 supports DisplayPort 1.4 so it works better with the Logilink adapter.

You can get USB-C hubs that don’t support USB 3.0 such as the Club-3d CSV-1534 or Cable Matters 201046-BLK. They are limited to USB 2.0 but will have 4 entire lanes of HBR2 or HBR3. 4 lanes of HBR2 supports 4K60 594MHz HDMI 8bpc or 4K60 533MHz CVT-RB 10bpc. The USB-C ports of these hubs is for charging only. You cannot connect a CAC-1517 to the hub. If you want a hub with USB-C ports, then get a Thunderbolt 3 dock. A Thunderbolt 3 dock can support USB 10Gbps and 4 lanes of DisplayPort 1.4 but are much more expensive than a USB-C hub.

If you need to use the HDMI port of the display, then consider a modern USB-C to HDMI 2.0 adapter. I think the Club-3d USB-C or DisplayPort to HDMI 2.0 or HDMI 2.1 adapters should support arbitrary aspect ratios. The CAC-1588 should be sufficient. I’m not sure why it would only give 4K30 for your setup.

HDMI 2.0 = 14.4 Gbps (after considering the 8b/10b encoding).
DisplayPort 1.2 = 17.28 Gbps (after considering the 8b/10b encoding).
DisplayPort 1.4 = 25.92 Gbps (after considering the 8b/10b encoding).

3840 x 1600 @144Hz 10bpc CVT-RB2 = 29.0 Gbps.
3840 x 1600 @144Hz 8bpc CVT-RB2 = 23.2 Gbps.
3840 x 1600 @120Hz 10bpc CVT-RB2 = 23.9 Gbps.
3840 x 1600 @120Hz 8bpc CVT-RB2 = 19.1 Gbps.
3840 x 1600 @100Hz 10bpc CVT-RB2 = 19.7 Gbps.
3840 x 1600 @100Hz 8bpc CVT-RB2 = 15.8 Gbps.
3840 x 1600 @75Hz 10bpc CVT-RB2 = 14.6 Gbps.
3840 x 1600 @75Hz 8bpc CVT-RB2 = 11.7 Gbps.

I think 10bpc is required for HDR which might require 4:2:0 or DSC for higher refresh rates. The user manual doesn’t mention support for 4:2:0 or DSC. You need EDID and DPCD dumps to learn the exact capabilities of a display and its DisplayPort ports. The EDID will list all the supported timings (they might differ from CVT-RB2). The DPCD info can be obtained from DisplayPort/USB-C to HDMI adapters as well. I think you can get DPCD in Linux with some commands. For macOS (Intel Macs), I made a tool called AllRez to dump all the display info including DPCD.

You can use CRU (Custom Resolution Utility) to examine the EDID and create custom timings. I would use edid-decode to dump EDID info to a text file.

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