Dual 2560x1440 screens - Cable Problems - How long is too long a cable run?

makaira

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I have dual 2560 x 1440 (ASUS 27") monitors connected to 4 PC's via a dual-display Aten 4 station KVM (CS1644).

I have one machine in a computer rack which requires a 10m cable run, the other three are at my desktop. I am attempting to run all the displays at 2560 x 1440 resolution.

I have all DVI-D Dual Link cables everywhere (the 10m run and the short 2m runs).
The SECOND SCREEN from the rack computer coming from a single ASUS GTX760 (the DVI-D socket) has issues - the monitor complains "Cable incorrect Please use Dual-Link DVI cable", and drops to some strange resolution despite being reported as 2650 x 1440 by the software.

On PC 1 next to the KVM with 2m connections a GTX660 Ti has no problems with dual 2560 x 1440 connections with the same driver. When I connect using the 10m cable to this machine the similiar second DVI point (the DVI-D connection) gives the same error message.

On PC 2 which uses Dual GTX760 displays (not in SLI mode) both the 2m and 10 m cables display without problem at desired 2560 x 1440 resolution when connected to the DVI-I connections on the graphics cards.

When the 10m cables are both connected to the DVI-D connections, the error returns on Both screens.

I conclude that DVI-D connected cable runs of 10 metres do not work at 2560 x 1440 resolution despite using "decent" cables with gold connections, but will work with a 2m cable connection.

The only solutions I see to get 2560x1440 on both screens from the computer in the rack are :
1- to try to fit dual GTX 760's into the rack computer - a real issue as this machine has multiple RAID controllers needing relocation and CPU's are already running at 88deg under heavy load.
2- To find a "converter/extender" for DVI-D cable - and perhaps break 10m cable run into less distance.

Has anyone got the latter to work (extender)?
Can anyone else see a solution that will not require moving the desk or rack?


Does anyone know (practical experience) what is the maximum length of a dual-link DVI-D cable running at 2560x1440 or 2560 x 1600?

 

makaira

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That may work, but I fear that'll require me to get a new KVM and a few extra Graphics cards, not to mention new cables.