Hi Phil, we received the PlugDebug log from your system – thank you for sending this!
Looking at the logs I can see the Philips TV only exposing a maximum 30Hz refresh rate and I do not see 60Hz appear when reading the monitor’s EDID information that is sent to the GPU. Our adapter shouldn’t restrict 60Hz from being delectable so this tells me that something else may be limiting the connection to 30Hz.
Can you confirm that the TV’s firmware is up to date? This can be found by going to Home > Settings > Update software > Search for updates > Internet (Recommended) within the TV’s menu.
Is 60Hz not achievable if the Philips 4K TV is the only connected display to the GTX 670 graphics card?
If the same issue occurs with the Philips TV as the only connected display the next thing we can try is creating a Custom Resolution within the Nvidia Control Panel to see if we can force 4K@60Hz.
Pending that information, the only specs sheet that I have been able to find from EVGA for your specific card is here --> https://www.evga.com/products/specs/gpu.aspx?pn=70FD7D03-C5A5-4114-8AB6-D2D4EC919BE8 where they seem to mention that the max digital resolution achievable is 2560x1600 (via a Dual Link DVI Only), but they make no mention to the capabilities of the DP (or HDMI) port. Of course, you are currently able to achieve higher than 2560x1600 over the DP port. Additionally, the Nvidia specifications page that I sent previously did make mention that UHD at 60Hz is achievable via DP, so I am seeing inconsistent information.