Questions about BenQ Gl2450hm

Yes it has, but not of high quality, e.g. hardly any bass. I would recommend external speakers. Would also be in the specifications ;)

Basically, a power cable is included and a small selection of AV cables (DVI) but unfortunately no hdmi cable :( hope this helps you.

60Hz

Maybe the HDMI connection is defective or you have to select the input manually. The Xbox works with the same cable on a TV, yes?

60HZ

Digitec includes a CH power cable.

24" stands for 24 inches (1 inch = 25.4mm), i.e. just under 61cm. This specification for displays is for the screen diagonal. With an aspect ratio of 16:9, the screen is about 48 cm wide and 36 cm high.

HDMI switches always have a little loss of quality and require another power supply. It is best to simply buy the correct cables so that one device goes in via HDMI and one via DVI. Then there is no loss of quality and it costs less.

If your computer/graphics card has 2 video outputs, e.g. 2 x HDMi or DVI, then yes!