HDMI to DVI is better. The output on your screen will be whatever outlet you're originally plugged into, not what you're adapting to. So if you are using your computer's hdmi port, you get hdmi output, if you're using the dvi port, you get dvi output. Since HDMI is better, HDMI to DVI is better.
I can only use the DVI port from the computer to connect to the hdmi port on my monitor. I just wondered if the DVI adapter that goes into the PC DVI port is better or if an adapter cable that has DVI and HDMI on the same cable is better?
Alright I understand. The first cable here will be better : https://www.amazon.co.uk/AmazonBasics-Adapter-Cable-Latest-Standard/dp/B014I8UL8U/ref=sr_1_7?rps=1&ie=UTF8&qid=1475686221&sr=8-7&keywords=dvi+to+hdmi+adapter
I always say keep it simple, and for your purposes this is all you need. The 2nd one just adds an unnecessary complication.