mini Displayport male to Displayport female, 4K@120 Hz adapter


#1

I’m looking for a miniDisplayport male to Displayport female adapter that supports Displayport v1.3 (4K @ 60 Hz and ideally 4K @ 120 Hz). Where can I find such an adapter?


#2

Hi Eric,

Thanks for asking. We haven’t seen any such adapters beyond DP 1.2. With Nvidia having released DP 1.4 GPUs, and Intel doing so next year, hopefully accessories will soon follow. (Though I suspect Plugable is unlikely to bring the specific adapter you mention to market.)

Thanks,
Gary


#3

mini DisplayPort and DisplayPort use the same signals. DisplayPort 1.3 has the same connector/pins as 1.2. It increases the bandwidth from 5.4 Gbit/s to 8.1 Gbit/s. I don’t think that increase is large enough to require new adapters. Read about DispalyPort 1.3 at:
http://www.anandtech.com/show/8533/ve…


#4

@joevt Thanks for the link - that’s a good article. I would assume that the difference in moving from v1.2 to v1.3 is that the latter does a better job in maintaining signal integrity (better isolation, matched signal lengths and impedance, etc.). I can only assume that is the reason why vendors, such as this: http://www.cablematters.com/pc-23-32-…
specifically indicate support for the 1.2 spec but remain quiet on the 1.3 spec.

Certainly, I could try to use a 1.2 adapter and drive it at the higher bandwidth. Can you (or anyone else) suggest the best part that might give me a chance?


#5

DisplayPort 1.1 was 2.7 Gbits/s, half of DisplayPort 1.2, so the jump to DisplayPort 1.2 was much greater than to 1.3. Well, each jump is 2.7 Gbit/s, but the first jump doubled the previous, and the second jump was an increase of only 50%.

Any DisplayPort 1.2 cable/adapter should work that is built to the DisplayPort 1.2 spec but only the passive cables/adapters that don’t have extra electronics for converting or splitting or whatever. mini DisplayPort is just a different connector shape, and does not require conversion of the signal.

Maybe vendors say 1.2 because they haven’t tested 1.3? I suppose it’s also possible they tested 1.3 and failed and don’t want to mention that.

What is your DisplayPort 1.3 source (GPU, and computer model if built-in) and destination (display model)?


#6

Certainly no harm in trying a DP 1.2 adapter in a DP 1.3 scenario! If you do try it, curious to hear how it goes.

(Though as a side note, we’ve worked with customers on many cases where DP cables and adapters such as you mention don’t hold up to max DP 1.2 throughput, much less functioning at 50% higher bandwidth.)


#7

Perhaps those cables or adapters were below spec.

From the displayport.org website:
https://www.displayport.org/cables/ho…

"Always buy cables from a reputable computer system or accessory brand. Or safer yet, buy a cable that is DisplayPort certified. DisplayPort certified cables are listed here:
https://www.displayport.org/products-…
"

The lists seem very short to me. Maybe the lists on the website are incomplete, or maybe there’s a lot of not certified stuff out there.


#8

We have a Sager NP9876 laptop with an NVidia GTX 1080. The laptop specs suggest the miniDP should support 1.3. The destination is a custom display solution that we are developing. The cable is also custom (developed by a partner of ours) that has a full displayport connector that we must connect to. We have been successful in connecting to a GTX 1080 in a desktop computer at 12.1 Gbps (4 lanes at 5.4 Gbps. This is a 4K video signal at 60 Hz). But when we connect to our laptop, it will only support half that (30 Hz). One hypothesis is that the mini-DP to DP adapter we are using is to blame. Right now, we are using the following adapter:
http://www.cablestogo.com/product/543…
I started this thread to see if anyone could point to ‘the best’ adapter maker out there - hoping that that would lead to more success…

I did not see one of these adapters as ‘certified’ on the displayport.org web site.


#9

All that being said, does Plugable sell an adapter that can convert HDMI output from the laptop to a full DP output - i.e. I’d need an HDMI male to DP female adapter (It would need to support HDMI 2.0.)?


#10

I suppose the custom cable is not detachable. If it were then you could use a single male mini DisplayPort to male DisplayPort thereby avoiding the extra connection which can add noise.

Funny how the description for that adapter does not mention whether it supports 60 Hz or only 30 Hz @ 4K.

For the desktop test, you could try a DisplayPort male to mini DisplayPort female adapter with your mini DisplayPort male to DisplayPort female adapter. If it works then you know there’s nothing wrong with your adapter.

HDMI to DP adapters exist but only HDMI 1.4 (4K@30 Hz). They use a USB connection for additional power (much like DP to Dual Link DVI). There’s a thread at club3d asking for a HDMI 2.0 to DP adapter. I guess there’s no suitable chipset available yet to create that solution.

Have you considered using DisplayPort from the USB-C ports? They should support USB-C DisplayPort alt mode so you could use a USB-C to DisplayPort female adapter. Also, you could use a plugable Thunderbolt 3 to Dual DisplayPort adapter and get two DisplayPorts from one USB-C connector.

Your description suggests you only need DisplayPort 1.2 (4K@60Hz). When you say it will only support half that, do you mean the operating system doesn’t let you choose higher than 4K@30 Hz? In that case, you need to update the graphics driver, add a custom resolution, or use a different operating system. If you mean that you get data corruption if you choose 4K@60Hz, then that’s probably a quality issue.

Doesn’t DisplayPort have link training so that it won’t try to use a higher bitrate than the cable allows? Is there a way to examine the DPCD? Intel graphics in Ubuntu shows some of the DPCD info. Link training info is in the DPCD somewhere. Otherwise some DisplayPort testing tool with breakout to some kind of logger is required. Plugable makes a PD sniffer. For DisplayPort, you need a DP AUX Channel Monitor.


#11

Your Thunderbolt 3 ports should support DisplayPort 1.2. They probably don’t support DisplayPort 1.3. I read that the next version of the Thunderbolt 3 chipset will be called Titan Ridge and will support DisplayPort 1.4.

Your Thunderbolt 3 ports should support two DisplayPort 1.2 streams on one port (through Thunderbolt 3), or a DisplayPort 1.2 stream on each port (I don’t think a motherboard manufacturer is allowed to make a Thunderbolt 3 port that can’t have video on it?) Your laptop product description does not mention more than one display over Thunderbolt 3 though. Maybe the graphics driver can use MST for more displays on a single port if they add up to less than a 4K @ 60 Hz display? I think Nvidia supports 4 displays total? The laptop panel counts as one display.


#12

@joevt You’re a wealth of information. I will review and will try some of these alternatives. Thanks!


#13