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Question Dell XPS 15 9500 won't connect to some external displays?

pete6032

Diamond Member
Dec 3, 2010
5,800
1,427
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I have a brand new Dell XPS 15 i7-10750H with Geforce GTX 1650 Ti. I have a thunderbolt dock for it. Dock has HDMI outputs. I also have two older Dell LCD monitors circa 2014. The monitors have DisplayPort and DVI, but no HDMI. I connected the dock to the laptop via USB-C, then connect the HDMI out from the dock to the monitors using HDMI to DisplayPort cable. Laptop refuses to recognize the monitors.

I was convinced the dock was crappy or maybe the display cables or perhaps driver issue so I updated all display drivers, tested the dock and cables with brand new set of monitors and everything works just fine. Seems like for whatever reason the laptop doesn't like the older monitors. Any idea why it wouldn't like older monitors?
 

Viper GTS

Lifer
Oct 13, 1999
38,048
367
136
You can't use an HDMI to DisplayPort cable that way. They're essentially unidirectional, and are completely passive. They rely upon the source device to recognize that what is attached is not DP and adjust its signaling appropriately. This advice does not apply if you are using an active adapter, but based on how you described it seems unlikely.

Using the HDMI outputs on the dock to connect to the DVI inputs on the monitors should work as the signaling is compatible and it's just a physical adaptation. Keep in mind you'll be limited to 1920x1200 @ 60 hz so if these are high resolution displays that rely on dual-link DVI you'd again need an active adapter to go from HDMI 2.0 to dual-link DVI or DP.

Something like this is what you'd need for the latter situation:

Amazon.com: HDMI to DisplayPort Adapter 4K 60Hz, Koopman HDMI to DP Converter Cable, Active HDMI 2.0 to Display Port Connector for Xbox PS4, Supports 1080P 144Hz Video Output : Electronics

Viper GTS
 

pete6032

Diamond Member
Dec 3, 2010
5,800
1,427
136
You can't use an HDMI to DisplayPort cable that way. They're essentially unidirectional, and are completely passive. They rely upon the source device to recognize that what is attached is not DP and adjust its signaling appropriately. This advice does not apply if you are using an active adapter, but based on how you described it seems unlikely.

Using the HDMI outputs on the dock to connect to the DVI inputs on the monitors should work as the signaling is compatible and it's just a physical adaptation. Keep in mind you'll be limited to 1920x1200 @ 60 hz so if these are high resolution displays that rely on dual-link DVI you'd again need an active adapter to go from HDMI 2.0 to dual-link DVI or DP.

Something like this is what you'd need for the latter situation:

Amazon.com: HDMI to DisplayPort Adapter 4K 60Hz, Koopman HDMI to DP Converter Cable, Active HDMI 2.0 to Display Port Connector for Xbox PS4, Supports 1080P 144Hz Video Output : Electronics

Viper GTS
Thanks I will have to try with hdmi to dvi cable then. Something like this? https://www.bestbuy.com/site/best-buy-essentials-6-dvi-d-to-hdmi-cable-black/6463442.p?skuId=6463442

Also why would they make an HDMI to DisplayPort cable like this if you can't go from hdmi to DisplayPort?

 

pete6032

Diamond Member
Dec 3, 2010
5,800
1,427
136
Yes, that cable should give you 1920x1200 @ 60 hz.

Viper GTS
Thanks, one last question. These monitors are 7 years old and their resolution is 1440 x 900. Why would Dell have put DisplayPort connectors on these monitors? Wouldn't the DVI connector have been sufficient? There should be no difference between DisplayPort and DVI since they're running at 1440 x 900?
 

Viper GTS

Lifer
Oct 13, 1999
38,048
367
136
Thanks, one last question. These monitors are 7 years old and their resolution is 1440 x 900. Why would Dell have put DisplayPort connectors on these monitors? Wouldn't the DVI connector have been sufficient? There should be no difference between DisplayPort and DVI since they're running at 1440 x 900?
When's the last time you saw DVI on a video card? Monitors easily last a decade or more for most people, producing a DVI only display in 2014 would have been really poorly received by basically everyone. Having both makes them usable with basically every video card produced from the GeForce 256 to a 3090 today.

Viper GTS
 

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