Welcome! I did not quite know in which department to put this problem, because I do not know what it concerns. The situation is as follows - I have a PC that I assembled, to be sure I will give the specification: Mobo Asus PrimeZ370-P, i5 8600k and Fera 3 on it, GTX1070Ti, from Gigabyte, 16G ram, 2400Mhz, ssd disk and hdd disk 128G and 1Tb respectively, Vero L2 bronze 600W. The above station is connected to the Lenovo Y25f monitor via a DisplayPort cable. And this is where the story begins - I often left my computer to sleep (or did not turn it off completely while downloading something). In the morning, turning on the screen again, it displayed "No signal, check input cable", then it went into sleep mode itself, and then it turned on again showing the same information. Most often it was helped by a hard reset of the computer with a button on the housing (I initially thought it was strictly PC fault, but read on). The situation repeated very randomly, but the climax came when I wanted to turn on the computer from 0. The PC did not post an image on the monitor at all, which scared me (damaged graphics is the last thing I wanted). Resetting the computer didn't help anymore, but with the headphones plugged in, I could hear Windows sounds when I pressed something on the keyboard. Therefore, what I did right away was replacing the DP cable with a different one and connecting it in a different port - the situation repeated itself. Being completely broken, I went to sleep - the next day the computer fired up normally and sent the image to the monitor. However, when the situation repeated itself - I disconnected the Display port and connected HDMI (probably newer, because 144Hz work through it). The above case was not repeated even once with a connected PC via HDMI cable (sic!). So I made my mind by connecting the cable and HDMI and Display Port, enabling DP image prioritization in the Nvidia panel, so when it did not work, I did not even know it, because it switched to HDMI quickly. Today, however, I disconnected HDMI for the test (to test this new Gsync, which works! ) and the situation repeated itself randomly this time - while browsing the internet (worth saying, it has not happened before). Dear friends, are you able to give me an idea after this essay? Apart from sending the monitor to Lenovo, of course. It is worth noting that I tried to disconnect the graphics and connect Mobo directly to the screen. However, it was with the help of the HDMI cable, which, as you can see above, works flawlessly. Hence, I exclude damage to the graphics (unscrewed, anyway, new art is bought). Thanks!
In particular, check out post # 11 and # 13 by MiroLord (similar cases to yours are covered there) and my last post # 14. Perhaps (or rather for sure) your cable is just like my 20 pin and therefore causing the problem.
Thanks! Generally strange, because one DP cable came with the monitor only, and the other one was purchased separately. I don't know how many pins they have in both of them, I haven't checked them yet, but both actually give the same effect. Reading that thread, I saw that "noise" can also occur, which is funny - because in fact such "snowing" of the image occurred once or twice. In that case, the problem is probably noticed, it's just strange that the producers keep flying in the air and do not say that something could happen.
Perhaps the producers themselves do not know what cables they pack into their devices. I didn't have the monitor together, so I bought it at a computer store. As you can see, such stores also do not know what they have, because theoretically such a cable is compatible. But as you can see, not really.
The manufacturer pushes what he has and I doubt they will check it. The lack of descriptions for these cables makes it difficult to tell if a given cable is 19 or 20 pins. They are sold simply as DisplayPort and nothing else, which is why such bricks come out later