1.4 Display Port KVM Switch - Triple Monitor - Two Computer
USB Interface (5-gigabit or 10-gigbit):
10-gig
Problem:
I have a new gigabyte FO32U2P 32" 4k, 240Hz oled. I am only able to get 200Hz instead of 240Hz with the L1Techs KVM. DSC is enabled, as far as I can tell. Set to DP 1.4 mode, not 2.1.
Other Notes:
Nvidia RTX 3090
two 32-in 60/75Hz side monitors
I also have a ConnectPro UDP2-12AP that I bought ages ago in covid and was never able to get fully working, even with multiple replacements. However, I was able to get 240Hz out of that with this monitor and one of the side monitors (only supports 2). It had some occasional flicker issues resolved by driver reset ater switching, as well as compatibility issues with my keyboard.
ports and compatibility are basically why I switched to the L1Techs. And it solved all those problems. Only the new 200Hz limitation is problematic now.
Whats the total length of the cable? We have a totally different design philosophy than connect pro, and it sounds like there is too much snr loss.
We support freesync by keeping the kvm from appearing as a device on the dp bus and it maintains accurate subtiming in thisbway. The downside is that the total length of both cables appears to the gpu as one long signal corridor. The losses of both cables in either side of the kvm are additive and they appear as ine long cable.
Try adding 1 no more than 2 ferrite cable clamps, one at monitor end, one at kvm end of pc cable (optional) or try shorter or higher quality cables. Fiber dp cables on both sides may be needed if you dont want to spend time finding a compatible cable pair
They’re 6ft cables. I can’t really get away with less, due to my setup being a desk side server rack.
The cables are these from Microcenter. They’re not UHBR20, despite the packaging saying so. The cable is marked up to UHBR13. https:// www.microcenter .com/product/637456/DisplayPort_20_UltraHD_16K_Cable_with_Latches_6_ft_-_Black (spaces added to bypass filter)
But I’m just using them as DP 1.4 cables with KVM until a good 2.1 KVM comes along.
I’ll try getting some of the ferrite clamps.
As for ConnectPro, don’t get me started. Absolute nightmare working with them.
I can confirm that those FIBBR fiber-optic cables work wonders. My display was having trouble connecting across my L1T KVM until I switched to these.
Buyer beware though, I believe that some of the cables listed on that Amazon purchase page are copper, not fiber-optic. Make sure to select a cable that is explicitly listed as fiber-optic. When I purchased mine, the 3M was the shortest that actually used fiber-optics. The difference is also reflected in the price!
Are those confirmed to work at even longer lengths? I tried them previously with the ConnectPro and still had issues. But I would be willing to try them again if I can get longer than 6ft, as it’s somewhat restrictive at that size.
Also, can you confirm if they’re UHBR20 / 80Gbps? When i last tried them 2 years ago, they were 40Gbps, despite saying 80.
Unfortunately, we have not bought these specific cables, however we did buy the predecessor to these cables and they were working with our Odyssey G9 Neo at 240Hz. This is the kind we had success with:
That particular kind doesn’t seem to be sold anymore, though. The link I sent you is to their “new” line of fiber optic. Maybe we can get @wendell to buy one for science?
Hmm for now I’d try 3x fibbr cables. The input 1, input 2, and output to that 240hz monitor. So, basically, fibbr the entire row tied to that monitor.
When he says the KVM sees it as 1 long corridor, he’s not meaning all 9x slots together, it goes by rows. pc length + pc 2 length + output length. The copper cabling can only do so much before the signal integrity degrades. In “pushing the limits” instances like this, you need all the bandwidth and signal you can get. That’s why fiberoptic is so great. Lossless quality from point a to point b.
Just tried the ferrite, doesn’t seem to have worked, but I haven’t been able to restart work computer yet, just personal. Do both need to be shutdown then restarted?
Okay, so got this one working… it was a weird one.
Ferrite didn’t work.
Got the fiber cables and they didn’t seem to be working either.
Decided to try DP 2.1 mode on the monitor because the cables are technically listed as 2.1… and that did it.
In fact, all of the “whole number” refresh rates unlocked. I hadn’t really realized that they were missing to begin with. With the old cables, 2.1 mode struggled to maintain a signal at all.
Really curious what the deal is with this. Maybe bad firmware or implementation of DP 1.4/2.1 on this monitor? Something about the cables, kvm, or monitor?
Prolly a firmware bug on the fo32u. Fhe 3090 literally is ohysically incapable of dp2.1. Glad its not the kvm tho i bought one of these displays ans a w6800 to help prototype dp2.1
