Macmini 2014 > 4k or 1080p TV?

Hi,

tomorrow I gonna buy a new TV because I have too much HDMI handshake problems (no signal vid / snow on screen) between my MacMini 2014 (Jarvis) and my ooold Philips 1080p

I hesitate between a 4k and just FullHD Samsung TV.

How does the Mini and its crappy videocard handle the 4K? Or should I just keep all in 1080p and let the TV make the upscale itself?

Thanks for your advices