680 GTX Samsung UN60HU8550 CAC 1070

5 replies

no matter what I tried I cannot get 4k 60Hz to work with my 680 GTX and Samsung UN60HU8550.
lower refresh at 4k 30 Hz work, 1080p 60Hz work, but not 4k 60Hz.
I tried to use the native windows resolution adjustment, I tried the nvidia control panel resolution adjustment, no luck.

It works on my 980 GTX displayport to HDMI 2.0 for 4k 60 Hz, but I bought this adapter to work with my old 680 GTX as media PC so I can use my 980 for gaming PC.

Is there a firmware update to try?

My cable looks significantly shorter than the picture on amazon, but the measurements seem to match what's on the website, I guess the picture is not to scale?

I contacted support and got the firmware to try using all the recommended settings
"custom resolution, set resolution to 3840x2160 at 60Hz and set Timing standard to CVT-RB (reduced blanking)"
But still cannot get 4k at 60Hz with 680 GTX.

Is there anything else I can try?

TV is good, cbale is good, adapter works ... leaves the grahcis card. i don't have 680 card here so i cannot duplicate .. sorry :-(
Please contact Nvidia for support on settings or which driver to use for the graphics card.

I had the same experience with GTX680 during the weekend. The Nvidia drivers does weird stuff when it sees EDID with HDMI on the DP ports. I believe it may select the same max rate (and weird color) settings as used on the HDMI output (wich is HDMI1.4), limited to 300Mpix/s.
I haven't verified this but if you can override that EDID somehow (removing 128 last bytes of the 256 byte EDID) you may get this going. There are some older threads on how to do this with registry hacks, but I haven't tested myself.

A hardware hack would be to get an ext box that overrides the EDID. I know of one box that can do that (The Gefen EDID detective), but it's made for DVI. Using adapters, it may work, but the high speed 4k60 signal are fragile and doesn't like adapters much.

I'd prefer if club-3d had some goodwill with Nvidia and get this fixed. This problem is also visible with the latest Pascal architecture; When using the adapter at 4k60, the colors are looking like 4:2:0 when its not.

Hi ost,

We have seen and heard that Active Adapters like our CAC-1070 do not work well together with all Kepler GPU based Graphics Cards. Our R&D did of course contacted Nvidia on the subject, but Nvidia is not "very open" to say the least, with regards to giving access/details to their drivers / software.
This is why we needed to add to the features of our CAC-1070 product that it does nto support Kepler GPU based Graphics.
Very sorry for the inconvenience.

I don't know if you write the firmware for the PS176 chip yourself, but It would be nice to have a special firmware to mask out the CEA block from the EDIDI to trick the Nvidia drivers to not see and enter HDMI mode. Did you ever experiment with this?

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