If you’re just looking for a graphics card for office / display purposes, and you’re not worried about gaming performance. My recommendations after having a look online:
- Nvidia GT640, it’s about 4 years old, 4k60hz on Windows / 4k30Hz on Linux - they’re going on ebay for about £25
Even though the card only supports HDMI 1.4, 4K60hz output has been made possible - http://www.tomshardware.co.uk/nvidia-kepler-4k-hdmi-1.4,news-48230.html
Nvidia GT730 - 4k60hz on Windows / ? Linux This card has the same ‘hack’ as mentioned above for the GT640
Nvidia GT1030 There is a passive / fanless version available for this card as well.