Displayport loses signal when connected to external GPU (and not with the integrated gpu)

[andreafaro.kio]

Hi guys, I'm here to ask for your help to understand what's happening with my displayport connection.
I have always used my Acer Predator X34 G-Sync monitor with Displayport, which allowed me to benefit from G-Sync and the overclock to 100 hz.
But unfortunately, my DP connection has started to give me some problems: it continuously loses signal, making it impossible to use.
Here is a video of the issue: https://youtu.be/OIXNY7O6QBU
Instead, HDMI connection works flawlessly.
I've tried every fix I could find on the forums:
-unplugging and plugging again only solves the problem temporarily, and after some minutes it starts to lose signal again
-I tested if the cable was totally plugged both in my gpu and monitor
-I tried to disable G-Sync
-I tried to reset my monitor
-I tried to reset my mobo BIOS
-I tried to purchase a new DP cable (https://www.amazon.it/AmazonBasics-Cavo-DisplayPort-metri/product-reviews/B01J8S7624/ref=dpx_acr_txt?showViewpoints=1)
-I tried to do a clean installation of my Nvidia drivers

Then I discovered something interesting: I removed my GTX 1070 (Gigabyte G1) and plugged my DP cable into my motherboard (Asus Z170-A) to use my integrated graphic card (Intel i7 6700k)... and I was shocked to see that my DP connection worked flawlessly!

This made me think the problem could be in my GPU. So I borrowed another gpu (a Gtx 1080) from a friend: unfortunately, my monitor gives me the same problem. So I suppose my gpu is not the problem.

Summary:
-Acer Predator X34 DP connection doesn't work when the signal comes from anexternal gpu (GTX 1070 and 1080)
-Acer Predator X34 DP connection works when the signal comes from my integrated gpu (Intel HD Graphics 530)
-Acer Predator X34 HDMI connection works in both cases (with both external and integrated gpu)

What do you think about it?
Is it possible that the monitor DP port has a poor connection and can't handle the gpu signal (but for some reason it can handle the integrated gpu)?
Thank you in advance for your answers

 

[ex_bubblehead]

MERGED QUESTION
Question from andreafaro.kio : "Displayport loses signal when connected to external GPU"

Hi guys, I'm here to ask for your help to understand what's happening with my displayport connection.
I have always used my Acer Predator X34 G-Sync monitor with Displayport, which allowed me to benefit from G-Sync and the overclock to 100 hz.
But unfortunately, my DP connection has started to give me some problems: it continuously loses signal, making it impossible to use.
Here is a video of the issue: https://youtu.be/OIXNY7O6QBU
Instead, HDMI connection works flawlessly.
I've tried every fix I could find on the forums:
-unplugging and plugging again only solves the problem temporarily, and after some minutes it starts to lose signal again
-I tested if the cable was totally plugged both in my gpu and monitor
-I tried to disable G-Sync
-I tried to reset my monitor
-I tried to reset my mobo BIOS
-I tried to purchase a new DP cable (https://www.amazon.it/AmazonBasics-Cavo-DisplayPort-metri/product-reviews/B01J8S7624/ref=dpx_acr_txt?showViewpoints=1)
-I tried to do a clean installation of my Nvidia drivers

All of this made me think it was for sure a problem of the DP port of my monitor (maybe poor connection).
Then I discovered something interesting: I removed my GTX 1070 (Gigabyte G1) and plugged my DP cable into my motherboard (Asus Z170-A) to use my integrated graphic card (Intel i6700k)... and I was shocked to see that my DP connection worked flawlessly!
Then I discovered something else: if i plug the DP cable in the port 2 and 3 of my GTX 1070, the situation gets even worse. In the second there is no signal at all, in the third there are a few seconds of signal, and then black screen. So the only DP port working in my GTX 1070 is the first.

Summary:
-Acer Predator X34 DP connection doesn't work when the signal comes from my external gpu GTX 1070 (works bad with DP1, doesn't work at all with DP2 and DP3)
-Acer Predator X34 DP connection works when the signal comes from my integrated gpu (Intel HD Graphics 530)
-Acer Predator X34 HDMI connection works when the signal comes from my external gpu GTX 1070

The most logical solution seems to be that the problem is in the DP ports of my GTX 1070. But it seems a little weird that all of 3 DP ports are broken...
What do you think about it?

MERGED QUESTION
Question from andreafaro.kio : "Displayport loses signal when connected to external GPU"

Hi guys, I'm here to ask for your help to understand what's happening with my displayport connection.
I have always used my Acer Predator X34 G-Sync monitor with Displayport, which allowed me to benefit from G-Sync and the overclock to 100 hz.
But unfortunately, my DP connection has started to give me some problems: it continuously loses signal, making it impossible to use.
Here is a video of the issue: https://youtu.be/OIXNY7O6QBU
Instead, HDMI connection works flawlessly.
I've tried every fix I could find on the forums:
-unplugging and plugging again only solves the problem temporarily, and after some minutes it starts to lose signal again
-I tested if the cable was totally plugged both in my gpu and monitor
-I tried to disable G-Sync
-I tried to reset my monitor
-I tried to reset my mobo BIOS
-I tried to purchase a new DP cable (https://www.amazon.it/AmazonBasics-Cavo-DisplayPort-met...)
-I tried to do a clean installation of my Nvidia drivers

All of this made me think it was for sure a problem of the DP port of my monitor (maybe poor connection).
Then I discovered something interesting: I removed my GTX 1070 (Gigabyte G1) and plugged my DP cable into my motherboard (Asus Z170-A) to use my integrated graphic card (Intel i6700k)... and I was shocked to see that my DP connection worked flawlessly!
Then I discovered something else: if i plug the DP cable in the port 2 and 3 of my GTX 1070, the situation gets even worse. In the second there is no signal at all, in the third there are a few seconds of signal, and then black screen. So the only DP port working in my GTX 1070 is the first.

Summary:
-Acer Predator X34 DP connection doesn't work when the signal comes from my external gpu GTX 1070 (works bad with DP1, doesn't work at all with DP2 and DP3)
-Acer Predator X34 DP connection works when the signal comes from my integrated gpu (Intel HD Graphics 530)
-Acer Predator X34 HDMI connection works when the signal comes from my external gpu GTX 1070

The most logical solution seems to be that the problem is in the DP ports of my GTX 1070. But it seems a little weird that all of 3 DP ports are broken...
What do you think about it?

UPDATE: I borrowed another gpu (a Gtx 1080) from a friend and it gives me the same exact problem. So I suppose my gpu is not the problem.
Is it possible that the monitor DP port has a poor connection and can't handle the gpu signal (but for some reason it can handle the integrated gpu)?

I think your GPU is hosed. It's not the DP ports themselves - it's the signals going to the DP ports. Is the GPU still under warranty?

Thank you for your answer, Scottray
Yes, luckily the gpu is still under warranty. What I don't understand is... If the gpu is broken, why is the hdmi signal from the gpu working fine?

UPDATE: I borrowed another gpu (a Gtx 1080) from a friend and it gives me the same exact problem. So I suppose my gpu is not the problem.
Is it possible that the monitor DP port has a poor connection and can't handle the gpu signal (but for some reason it can handle the integrated gpu)?