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How to have Latitude 7490 to use 4k display with 60Hz?
I have a Dell Latitude 7490 laptop with i7 8th Gen CPU + Intel UHD Graphics 620. As a display I have Dell U2718Q that is capable for 4k resolution.
How can I have the laptop to use display in 60Hz through dock? Currently I have a WD15 dock but seems that it can only output 30Hz per it's specification.
Does TB16 or D6000 work with 7490 and could either output 60Hz with correct DisplayPort cable?
jphughan
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May 24th, 2018 08:00
Building on @DELL-Alasdair R's answer, the TB16 will only do 5K resolution with certain systems, namely a few Precision models, and only when they're in a certain configuration, namely "Graphics special mode". The Latitude 7490 does not support that, so with the TB16 you'll be limited to 4K at 60 Hz, although you could run two of those. As for the D6000, the link Alasdair posted for the D6000 points to the TB16 unfortunately, but it can run either a single 5K display or three 4K displays all at 60 Hz, regardless of the system model. However, the D6000's use of DisplayLink introduces several other drawbacks compared to the other docks that tap into the native GPU outputs.
Also note that in order to use the TB16, your system needs to have Thunderbolt 3, which I believe is optional on the Latitude 7490, not standard -- so check that. The easiest way is to go into your BIOS Setup and go to the Thunderbolt Configuration section; if everything is grayed out, you don't have Thunderbolt.
Another option that would work even if you didn't have Thunderbolt would be a USB-C to DisplayPort cable/dongle. Make sure you do NOT use a device that attaches via USB-C and includes other functionality, such as the DA300. If you want 4K at 60 Hz, your entire USB-C connection needs to be used for video output; if you use a "multi-function" dongle/adapter, then your display bandwidth gets cut in half.
Finally, if you DO have Thunderbolt but want a less expensive option than the TB16 dock, you could buy a Thunderbolt 3 to Dual DisplayPort adapter, which will allow you to run dual 4K displays at 60 Hz.
DELL-Alasdair R
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May 24th, 2018 02:00
Hi tlaukkanen,
The wd15 supports up to 2560x1600 @ 60Hz:
http://www.dell.com/support/article/us/en/04/sln296829/how-to-use-and-troubleshoot-the-dell-dock-wd15?lang=en
Whereas the TB16 will support up to 5120 x 2880 @ 60Hz:
http://www.dell.com/support/article/us/en/04/sln301075/how-to-use-and-troubleshoot-the-dell-thunderbolt-dock-tb16-?lang=en
The D6000 will also support 5120 x 2880 @ 60Hz:
http://www.dell.com/support/article/us/en/04/sln301075/how-to-use-and-troubleshoot-the-dell-thunderbolt-dock-tb16-?lang=en
I hope this helps...
tlaukkanen
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May 29th, 2018 12:00
Thanks for detailed answer!
Yes, as you said it doesn't seem to be so trivial to check if my laptop even has a Thunderbolt port :Smile: So this is what I see in my BIOS settings, I guess this means that I might be able to get 60Hz 4K by upgrading to TB16 dock?
jphughan
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May 29th, 2018 15:00
Unfortunately uploaded images are only visible to the person who posted them and to Dell reps, so I can't see what you posted. If you upload it and post the share link here, I can look. But if your Thunderbolt Configuration options are NOT grayed out, then you have Thunderbolt. Other ways to check would be to look at the USB-C port; typically if it supports Thunderbolt, you'll see a Thunderbolt logo there. Another option would be to go to support.dell.com, enter your Service Tag, and check the Original System Configuration page looking for something like Thunderbolt, TBT, or TBT3.