Display port to HDMI cable which works for full 4K/60 4:2:2 full ??

[aoaaron]

So, I've been using a few old cables I've found around the house for DP to HDMI and they all cap out at 4k/60. none supporting proper 4K/60.

Any suggestions on dongles or cables which will do the job? I've already bought 2 so far which seem to be duff ones.