Widescreen Gaming Forum

Hello

I´m not a top of the top user, but i know some basic things to solve a
problem, but this one is transcending Me, Nvidia, Asus (not a good support),
and many cable stores, a no one have a solution, so far after 2 weeks of
reading and posting in most of the forums that i cross, i see myself in this
one, with more experience people, so i´m going to try to explain what is
going on, and maybe i have some luck, because i´m completly stuck.

Let´s start from the beginning

I have an Asus PG278Q and an Asus G750JX, hooked up with a mini displayport
to displayport cable; i was using it with an Asus VG248QE, and at the
beginning the notebook didn´t detect more than 85Hz, so i take the laptop to
a store, i get it hooked up with a thunderbolt adapter from Apple to HDMI,
and somehow it enable the displayport, and when i get home, and plug in the
same cable, the display was recognized has a 144Hz one.

Now i bought the PG278Q, and what happens is, every single time i hook up the
cable, i get 85Hz, i try to create a costume display resolution with 144Hz,
says yes it´s ok, but doesn't show up in Nvidia Control Panel, and the Max
that i can get is 100Hz. so....:

First - I RMA the display, they brought my another one, i test it, same thing
85Hz top, with the driver of the Cd that came with the display, so i
installed the last version of Nvidia drivers, and i always have to try to
create the 100Hz customization, i get a "No Range" message, and even if it
doesn't appear, i have to do this, so the NVCP, after close it and open it
again, show me at least the 100Hz option.

Second - I tried almost all Nvidia drives from 340 and above, same thing, he
only shows me 85Hz Max, then i try the same steps to create the 144Hz, same
process has i described above, and when i close and reopen the NVCP, 100Hz
are shown.

Third - I made a complete factory reset to my laptop, after this, and without
any update installed, i plug in the display, 85Hz shown up, and then i try to
create the 144Hz, sends me a messege, saying that the display doesn't support
that refresh rate.

Four - I install the 340 Nvidia drivers that came with the cd of the display,
and install the only drivers that the display have, and nothing, same story
from the beginning, 100Hz max, and doesn't let me create the 144Hz.

Five - I go to a store (Mediamarkt in this case) and saw one working, they
have it plug in to a ROG tower with a GTX980, and they only tell me that they
plug it in and that´s it, no drivers of the display where installed, and the
144Hz appears, with no problems.

Six - I took my laptop there, hooked it up to that display that was working,
and with my cable, same thing

Seven - i try to force the resolution with some program that i can´t
remember the name, but no luck

Eight - I RMA again, got a new display, and same thing

So, i´m running out of options here, really this is the most strange thing
that happen to me.....so i contact Accell, because i saw that they where DP
certified, explain my situation, and they told me:
" Accell B143B-007B can support 2560x1440 @ 144Hz. However we cannot be sure
that using this Accell cable will resolve your issue.
Note that Thunderbolt and Mini DisplayPort are two different protocols, even
though they share the same physical connector. A Thunderbolt connection may
not be able to support 2560x1440 @ 144Hz."

I contact cablemasters
"If the cable you are using is only 6 feet I am guessing it is something to
do with either the graphics card or the monitor. Most 6 foot DP cables can do
4k at 60hz which is more bandwidth than those refresh rates you are trying to
get at 1080p. Our cable can support that but unfortunately we do not have a
way to ship to Portugal"

This last one (Cable Masters have a Mini Displayport/Thunderbolt compatible
cable to Displayport, in there description, i left me thinking if it isn´t
the cable...

in the end, my question is, what is going on here, can someone please help me
getting 144Hz?
Is there any program that can test my mini displayport/Thunderbolt port?

i really hope i can get one single answer please.

Thank you my friends

I checked the spec sheet on the laptop. It doesn't say what version of DisplayPort the outputs are. I think you need DP 1.2 to drive a 144Hz refresh.

Thank you my friend for your answer, but I can ashore you that this is a 1.2 cable here's the link of it http://www.chiptec.net/acessorios-diver ... l?___SID=U

You can see all the specs here

https://www.asus.com/ROG-Republic-Of-Ga ... OG_G750JX/

they say 1 mini-displayport and 1 Thunderbolt, but has you can see in the screenshot, they are in the same place

From the testing you've described it doesn't sound like an issue with the cable or the monitor, it's an issue with the laptop, as skipclarke suggested. Perhaps the GPU or motherboard only uses a 1.1 Displayport, which wouldn't be able to drive a 2560x1440 display at 144 Hz.

One thing that you could try to test further is lowering the resolution and seeing if higher refresh rates become available. If so, that would confirm that the laptop's displayport simply can't drive the full resolution and full refresh rate of your monitor.

If that's the case, you'd be better off returning the monitor and getting one with a lower resolution if you still want to hit 144 Hz.

i have tried that my friend, in all resolutions 85Hz is the Max.

Thanks for your answer my frend

I see you have also posted here about your issue:-
http://www.monitortests.com/forum/Threa ... e?pid=4287
https://forums.geforce.com/default/topi ... /?offset=2
https://rog.asus.com/forum/showthread.p ... Hz-Problem

The monitor does confirm that it is DisplayPort 1.2 compatible.

Looking into the laptop in more detail I read that it sports a Nvidia GTX-770M GPU, a chipset which is compatible and has been issued with the Displayport 1.2 connectivity.
According the the Nvidia site the GT-770M GPU chipset is able to drive 3840x2160 resolution, although it does not state at what refresh rate, according to my bandwidth calculator tool 3840x2160@85hz would be possible over Displayport 1.2.


The cable you purchased does not specify if it is DP 1.2 compatible, however it does state that it is a plain DisplayPort cable type.

-Source

DisplayPort 1.2 transmits data using the HBR2 mode.

To be able to drive 2560x1440@144hz you require 12.74Gbit/s of bandwidth, something of which only displayport 1.2 will handle.

Displayport 1.2 has a recommended maximum cable length of 3 meters, which your 2 meter cable is of cause inside of this maximum.


Given the feedback you have provided over your various posts I would conclude that the issue could be with an Nvidia driver or the unbranded cable you have purchased.

Please ensure you have installed the latest nvidia drivers provided by Asus for your laptop - http://dlcdnet.asus.com/pub/ASUS/nb/Dri ... 133788.zip

If this continues to be an issue then please try with an alternative brand displayport cable.

Good luck!

_________________
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Thank you very much my friend for your kind answer

has you might understand, i think that in different forums are different people with other knowledges, but i had no luck in 2 weeks, from talking to Nvidia, Asus, and some forums, but i really really thank you for your attention.

I´m going for the new cable, http://www.amazon.co.uk/dp/B00A7R9I22/r ... 71_TE_item , i talked do accell, and from the displayport.org, they say it´s certified displayport cable.

So when it get´s here, i will feedback my friend.

Thank you very very much for your analysis and your kind answer.

Personally, I think it is the output on the laptop. The specs page you link to (same one I found), only describes it as "mini DisplayPort" and "Thunderbolt". Based on this, I would assume it is the original "Thunderbolt (1)" and not the newer Thunderbolt 2.

According to the Wikipedia page, Thunderbolt 2 added support for 20Gbit/s and DP 1.2.

https://en.wikipedia.org/wiki/Thunderbolt_(interface)#Controllers

But it can't be the output or else I couldn't reach the 144Hz on the VG248QE, and play in 3D, don't you think this is strange? I get the 60, 120, and 144Hz, in the VG, in this one I only get 85Hz top, and the 100Hz appears after I try to create it,without success, because I get a black screen, and then when the image comes, the 100Hz option appears, also 120hz I get a black screen, but in this case I have to force the restart, or I don't see nothing, the 144Hz also works, but doesn't stay costumized in the NVCP. The PG278Q it's not thunderbolt 2, it's like the VG , only with more better quality and higher resolutions.