1440p is also called QHD (quad high definition) or WQHD (wide quad high definition) and is a display resolution that measures 2560 x 1440 pixels. This resolution is also commonly referred to as 2k.
Speedstep, dual link DVI does support QHD, so it's not accurate to claim that DVI can never run QHD. And the DP outputs on the E-Port docks don't support DisplayPort 1.3, so I'm not sure why you posted an image about DP 1.3 capabilities. As for QHD being commonly called 2K, it's true that many people do that, but it's also incorrect. 2K is a film resolution of 2048x1080, but when used in the consumer space technically refers to the nearest and slightly LOWER resolution of 1920x1080 -- just like 4K is technically a film resolution of 4096x2160 but when used in the consumer space refers to a lower resolution of 3840x2160. In order to avoid confusion, the recommended ways to refer to 2560x1440 are QHD or 1440p. 2K is ambiguous because so many people use it incorrectly.
@MaricopaDon The DVI outputs on the E-Port docks are only single link DVI, and therefore only support 1920x1200. As for the DP outputs, there are two generations of the E-Port and E-Port Plus. The first generation, identified by black USB ports on the rear, only supports DisplayPort 1.1a and USB 2.0. The second generation, identified by blue USB ports on the rear, supports DisplayPort 1.2 and USB 3.0 on the rear USB ports. Both generations can support QHD, and the second generation can support 4K 60 Hz -- although dual 4K 60 Hz support depends on the system you're using with it. The E7470 would only run dual 4K 30 Hz or single 4K 60 Hz even with a second gen dock due to the internal setup of the system.
Typical DP to HDMI/DVI cables work by relying on the source DP output supporting Dual Mode DisplayPort, which allows the source DP output to fall back to native HDMI/DVI signaling. The E-Port docks support that, but they might only support an HDMI/DVI signaling standard that allows up to 1920x1200. The fact that a DP output can run a certain resolution when using native DP signaling does NOT mean it can also do that when using native HDMI signaling through Dual Mode DisplayPort. Active adapters are another story because in that case the source DP output is still using native DP signaling, in which case the relevant factor would be the standards supported by the internal converter chip in the adapter.
while old, maybe it is still useful for somebody. Thanks for the input here, which helped us assess compatibility of QHD screens with 2nd generation E-Ports.
It is quite difficult to find official information about the E-Ports from Dell (there is no specification PDF which mentions e.g. the DP version, etc). The only way for me was via wayback/web-archive.
Both support indeed DP 1.2, but (according to the description) only Single link DVI (while pinout is Dual link DVI). Both support daisy chain).
Looking at this thread, it might be advisible to upgrade the MST firmware to prevent any flickering on the display port: https://community.spiceworks.com/t/e5450-docking-issues/395535/370 (latest firmware is from 2017, you can view the installed firmware with the "-v" flag, see readme inside the zip file)
So, 3 screens worked for us with a E7470 i7 (HD Graphics 520) and a E-Port advanced USB 3.0 immediately:
1x FHD 1920x1080 60Hz on the laptop
2x QHD 2560x1440 60Hz via the 2 Displayports on the E-Port
Also the DP ports of the E-Ports are DP++ (dual-mode) compatible, so using a passive DP->HDMI adapter also worked to drive the screens in QHD resolution.
speedstep
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December 10th, 2020 07:00
QHD requires display port. DVI NEVER allows QHD.
1440p is also called QHD (quad high definition) or WQHD (wide quad high definition) and is a display resolution that measures 2560 x 1440 pixels. This resolution is also commonly referred to as 2k.
jphughan
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14K Posts
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December 10th, 2020 08:00
Speedstep, dual link DVI does support QHD, so it's not accurate to claim that DVI can never run QHD. And the DP outputs on the E-Port docks don't support DisplayPort 1.3, so I'm not sure why you posted an image about DP 1.3 capabilities. As for QHD being commonly called 2K, it's true that many people do that, but it's also incorrect. 2K is a film resolution of 2048x1080, but when used in the consumer space technically refers to the nearest and slightly LOWER resolution of 1920x1080 -- just like 4K is technically a film resolution of 4096x2160 but when used in the consumer space refers to a lower resolution of 3840x2160. In order to avoid confusion, the recommended ways to refer to 2560x1440 are QHD or 1440p. 2K is ambiguous because so many people use it incorrectly.
jphughan
9 Legend
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14K Posts
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December 10th, 2020 08:00
@MaricopaDon The DVI outputs on the E-Port docks are only single link DVI, and therefore only support 1920x1200. As for the DP outputs, there are two generations of the E-Port and E-Port Plus. The first generation, identified by black USB ports on the rear, only supports DisplayPort 1.1a and USB 2.0. The second generation, identified by blue USB ports on the rear, supports DisplayPort 1.2 and USB 3.0 on the rear USB ports. Both generations can support QHD, and the second generation can support 4K 60 Hz -- although dual 4K 60 Hz support depends on the system you're using with it. The E7470 would only run dual 4K 30 Hz or single 4K 60 Hz even with a second gen dock due to the internal setup of the system.
Typical DP to HDMI/DVI cables work by relying on the source DP output supporting Dual Mode DisplayPort, which allows the source DP output to fall back to native HDMI/DVI signaling. The E-Port docks support that, but they might only support an HDMI/DVI signaling standard that allows up to 1920x1200. The fact that a DP output can run a certain resolution when using native DP signaling does NOT mean it can also do that when using native HDMI signaling through Dual Mode DisplayPort. Active adapters are another story because in that case the source DP output is still using native DP signaling, in which case the relevant factor would be the standards supported by the internal converter chip in the adapter.
PI_2007
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2 Posts
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September 5th, 2024 09:30
Hello,
while old, maybe it is still useful for somebody. Thanks for the input here, which helped us assess compatibility of QHD screens with 2nd generation E-Ports.
It is quite difficult to find official information about the E-Ports from Dell (there is no specification PDF which mentions e.g. the DP version, etc). The only way for me was via wayback/web-archive.
1) Advanced (legacy connectors) E-Port USB 3.0 (2nd gen): https://web.archive.org/web/20180315063508/http://www.dell.com/en-us/shop/accessories/apd/331-6304
2) E-Port USB 3.0 (2nd gen): https://web.archive.org/web/20180520020519/http://www.dell.com/en-us/shop/accessories/apd/331-6307
Both support indeed DP 1.2, but (according to the description) only Single link DVI (while pinout is Dual link DVI). Both support daisy chain).
Looking at this thread, it might be advisible to upgrade the MST firmware to prevent any flickering on the display port: https://community.spiceworks.com/t/e5450-docking-issues/395535/370 (latest firmware is from 2017, you can view the installed firmware with the "-v" flag, see readme inside the zip file)
So, 3 screens worked for us with a E7470 i7 (HD Graphics 520) and a E-Port advanced USB 3.0 immediately:
1x FHD 1920x1080 60Hz on the laptop
2x QHD 2560x1440 60Hz via the 2 Displayports on the E-Port
Also the DP ports of the E-Ports are DP++ (dual-mode) compatible, so using a passive DP->HDMI adapter also worked to drive the screens in QHD resolution.
(edited)