I do not know this, as I do not operate the cable with such resolutions.

The manufacturer's website states: DisplayPort to HDTV cable for transferring content from, for example, your graphics card (DisplayPort) to your TV (HDTV) - with a quality of up to 1920x1080 @60Hz, including audio transmission!
I myself use it far beyond the specification. 2560x1440 with 120 Hz doesn't cause any problems yet. I would buy it and give it a try.