3440 Fullscreen without gpu upscaling is a lower res so if that works it confirms it’s probably snr and not something more exotic. Something at least.
So far so good on the 6900 at 5120 with your same settings, will swap to fe3090
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I’ll be honest, I didn’t fully understand the difference between Display and GPU for display scaling. Now I do so thanks for that.
So with the display actually set to be 3440x1440, the signal stays. There is however obvious visual noise in the signal that you can see in this video. This is with my two fiber cables. Honestly I’m shocked that 4 metres of fiber cable is enough to create this kind of noise!
Yeah I think one or more of the cables are dodgy or you’re the unluckiest person in the world with cables or something’s up with the power brick. If you have a passive adapter the us power brick will work with a different connector. It unsnaps and I plan to send you a uk style plug to try, probably also with a club3d cable or two. It’s weird it works stand alone but this does confirm snr problem.
I’m also trying to track down your original KVm since you did an exchange swap since my initial reply to you went to your spam or something I didn’t get to go hands on with the first failing kvm to try it.
There is no way two 0.8m cables would be doing that normally too so ?? If not for swapping KVMs I’d be leaning toward KVm too. Problem is the g9 neo is really really picky with cables too from my experience soooo
We will keep at it and figure out a solution.
So far fe3090 is good
Also rocking native res not 3440.
And confirmed it’s not really hdr or anything it’s just snr which is a relief for me 
But we’ll get it sorted…
Thanks Wendell. Honestly I’m glad it’s the cables too. I’ve ordered a couple of club3d cables myself, should come later on in the month. One 1 meter and one 2 meter. Knowing my current cable luck though… might not turn out so well 
Thanks for being so thorough and checking yourself with a 3090. I really thought just getting a couple fiber cables would solve any cable-related issues, you learn something new every day!
Kind of wish I had one of those fancy cable testers after all this. Think they cost an insane amount but wow would it be worth it just to find out which cables are good and which are trash
So there is a sliiighghtttttt worry on my side now that something in one of the cables degraded the port connections in the KVm. Hence my quest to find your old one to test lololololol
I will work on that this weekend
Ah right, I see. Well I hope you can find it… and I hope nothing’s actually wrong with it
So, because we discovered that there was in fact poor snr with my cables, I went and bought 7 Club3D 1 metre cables with the goal of finding two that worked together. I labelled them A-D and 1-3 as I got them in separate orders and had already tried 1-3. A-D were fresh, new cables received today.
Here are my test results so far (recorded time is in minutes running cyberpunk at 5120x1440 with HDR):
I’ve still got quite a few combinations to go, but it’s not looking promising. I’m trying to be as careful with the cables as I can – how likely is it that I’m damaging them enough to stop them from working?
Other than that… yeah. In all likelihood I’m looking at 7 club3d cables that aren’t good enough to properly drive this monitor. Am I really that unlucky?
Seems unlikely. It’s possible you’re getting a hum of snr interference from something? But this would be the weirdest troubleshoot ever.
I will have your original to test soon too.
Just out of sheer curiosity do you have a passive plug adapter for the original power brick?
Is this the plate you need to use naively?
The power brick thancomes with the kvm is fine for your power spec you just need a passive adapter to plug it in
Or this one?
It’s the first image, the one with three prong things. The second one is an EU plug, the UK uses its very own fancy plug type because we like to be annoyingly different.
I don’t have one that fits the adapter, so if you could send one that would be fantastic.
Could other cables be causing the snr interference? Or could USB cables cause it? I noticed that the KVM seems to be getting powered by my powered USB hub that I’ve plugged in to the rear USB 3 port of the KVM. I’ve been disconnecting it along with the actual power cable every time I change DP cables, then plugging in the actual power cable first just to try and make sure it’s drawing power from the proper source.
Maybe I should be testing the device with nothing else plugged in, and far away from any other cables. I will continue testing but yeah, it’s looking fairly grim so far.
I appreciate your help figuring it out. It’s for sure outside the norm.
I was thinking about a passive adapter like this one:
To use with the bundled power brick.
It’s picking up noise from somewhere… it’s quite baffling.
hey, I have some new intel from trying a bunch of stuff on my end.
I updated my nvidia driver on my ancient machine and I found something, maybe
can you use the nvidia control panel and setup your control panel the same way:
(sorry its sideways)
I’ve finally got some good news! After trying 26 different combinations of DP cable, I have Finally found two cables that work well together!!
With cable 1 as the PC → KVM cable, and cable B as the KVM → monitor cable, it’s been holding a signal for 4 1/2 hours and counting!!
Why did those same two cables the other way round only work for 8 minutes? I have 0 clue, absolutely none. But this really seems to work. I already tried them for 3+ hrs yesterday, and today I’m going to see just how long the signal lasts for. So far… it doesn’t seem to be stopping 
I really think my problem all this time has just been cables. Which I would say makes me very, very unlucky 
If these two cables really work flawlessly then… wow. I really had to put some work in to get this thing going! Totally worth it lol
It’s possible those are fakes, some of them. Look very closely at the wire diameter and the cable housing.
The last time I got fake cables they were from Amazon and the cable end housing was noticibly different.
I am tracking a maybe separate issue with the g9 now. Since updating to the very latest Nvidia drivers its not enabling dsc for 120/HDR/10bit but is enabling dsc for 240.
It’s possible 240hz will work better for you than not if this is a driver issue. I had not updated the driver on my machine in probably 3 months.
Fakes you say? Cripes, I hadn’t considered that. They all came in the same packaging, and they come from scan.co.uk which is a very legit online hardware retailer in the UK. I will inspect them though… it’d be nuts if they weren’t legit.
As far as I know 120Hz has never used DSC with the G9 neo and my 3090. The way I’ve noticed DSC being used is scanlines in bright colours, normally orange or blue. I try to use settings that avoid scanlines as much as possible, so no 240hz and no VRR Control. I think you’re right, 240Hz would be easier to drive but I’d much prefer to have a scanline-free 120hz like this!
Also if this is the end of this journey, really thank you so much for the support. It’s been a really cool experience, I’ve showed this thread to a couple of my tech-y friends and they’ve been amazed haha
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