Bad DP Cable or too long?

[Spotty]

I purchased a 3m Displayport - Displayport cable for my monitor since the included 1.5m cable that came with the monitor isn't enough to properly reach from the monitor to the computer, and with my desk layout I can't move either closer to the other. It needs to run 1440p 144hz.
I bought an "Alogic Displayport - Displayport v1.2 3m" cable. Both the information published from the seller, and the product information claim it can do 21.6gbps which should support 1440p 144hz (~14gbps). However, when I plugged it in and tried to use it, it would detect at 1440p 144hz in the Nvidia settings, but would constantly flicker on and off every few seconds.

See video: Monitor Dp-1.m4v

 

Definitely the cable at fault, as when using the 1.5m cable it works flawlessly.
Is it a bad cable, or is 3 metres too long to carry a display port signal without loss? Going to try and return the cable either way. Would a 2m long DP cable work or is that too long as well?

[Spotty]

1 minute ago, VegetableStu said:

Try a 2m cable first? I'm guessing 3m might be bordering a bit on signal integrity with higher bitrates without using an active cable o_o

Don't have any on hand. The only DisplayPort - DisplayPort cables I have is the 1.5m one that came with the monitor (works fine) and the 3m one I just bought (doesn't work).
From what I've found so far the 2m cables seem to cost in the region of AU$35-$45 for ones that claim they can deliver v1.2 bandwidth. Was actually cheaper to buy the 3m cable than the 2m ones (the 3m cable was AU$25).

Lots of cheaper 1.8m long cables for $5-$10, but they have warnings on the page stating they can only deliver 1080p signal - not 4k, so they won't work with 1440p 144hz. If needed I could probably get away with 1.8m length, it will just mean that I probably won't be able to route and hide the cable through the cable port in the desk.
 

1.5m is pretty much a direct path from monitor to PC, and it only just has enough length to be plugged in.

1.8m would probably be fine just to leave a bit of slack in the cable, but probably not enough length to neatly route/hide the cable.

2m would give me enough length to route the cable through the cable port in the desk behind the monitor and then down to the graphics card, but probably not enough length to fully hide it behind the desk (which at this point with all the other cables all over the place isn't a huge concern).
3m would be ideal though as I could neatly route the cable through the port hole and route the cable below the desk and around to the PC to fully hide it, but if it can't carry the signal then I'll just have to go with something shorter.

[Alex Atkin UK]

Yeah that definitely sounds like signal integrity issues.  Unfortunately cables always make bold claims about what they support but if it works will generally be down to the luck of how poweful the GPU signal is and how sensitive the monitor is.

 

My previous monitor had huge issues with HDMI 1080p 60Hz at 3m, new monitor runs fine on DP 2160p 60Hz at 5m.

[Spotty]

20 minutes ago, Alex Atkin UK said:

Unfortunately cables always make bold claims about what they support but if it works will generally be down to the luck of how poweful the GPU signal is and how sensitive the monitor is.

If it helps, I'm using a GTX 1080ti with the Acer Predator XB271HU monitor. Not sure if it is important, but I'm also using Gsync.

 

Put in a refund request for the 3m cable. I guess I will just buy a 1.8m (6ft) cable and I'll just have to live with the lack of tidy cable management.

[Alex Atkin UK]

Cables are a nightmare, I've been through so many HDMI cables trying to get reliability over 10m but then got lucky when I moved to DP as it just worked.

 

It certainly didn't help when I had a GTX 970 that had mini ports as the adapters to make them full size further reduces the signal reliability, as generally every additional connector reduces the signal strength.

[Glenwing]

2 hours ago, Spotty said:

Is it a bad cable, or is 3 metres too long to carry a display port signal without loss? Going to try and return the cable either way. Would a 2m long DP cable work or is that too long as well?

It depends on the quality of the cable. Try using an Accell cable.

[Spotty]

4 minutes ago, Glenwing said:

It depends on the quality of the cable. Try using an Accell cable.

Looks like Accell brand cables aren't sold in directly Australia. I can order from Amazon US, but it will cost $30 + $15 delivery + (maybe?) import duties/tax, so around $50+.
https://www.amazon.com.au/Accell-DisplayPort-Cable-Locking-Latches/dp/B0098HVZBE/ref=sr_1_1?ie=UTF8&qid=1536049130&sr=8-1&keywords=Accell+displayport

I noticed that they have a 6.6ft (2m) and 10ft (3m) cable options. Being a better brand, would their 3m cable work for 1440p144hz with Gsync without signal loss/that flickering on and off?

Any other recommendations for brands of cables that might be available in Australia without importing from US? Is there anything I should look for when shopping for a cable that will tell me whether it's good or not? I thought I was doing it right by buying a branded cable which claimed to support the signal I was using - as opposed to all of the cheap unbranded Chinese cables that claim only 1080p.