To catch up about Ultra HD 4K resolution please see related article What is 4K Ultra HD – Quick Introduction.
All new 4K Ultra HD monitors have HDMI and DisplayPort and number of those ports varies depending on the manufacturer. Unfortunately the fact that you have such a physical port on your computer does not give you certainty that it will handle a 4K display.
In desktop computers you can upgrade graphics card, but laptops owners must unfortunately replace the laptop.
HDMI
Version 1.0 – 1.2a – max FullHD (1920×1080)
Older desktops and laptops (at least 5 years) are usually equipped with HDMI version 1.0 – 1.2a Those versions have maximum transfer rate of 4.95 Gb/s (image + sound + control data). Unfortunately, it is not enough for UltraHD resolution. These versions allow only achieve a maximum of Full HD video (1920×1080).
Version 1.3 – max resolution 2560×160
Similar to version 1.0 – 1.2a but this allows you to get resolution of only 2560×1600.
Version 1.4 – UltraHD in 24bit and 30Hz
The image will be UltraHD but transfer rate of 10,2Gb/s allows only for a maximum of 24-bit color depth and maximum frame rate of 30 frames per second. This is enough to work on static materials such as documents or spreadsheets. Also enough to watch movies at a resolution of UltraHD (most movies use 24/25 frames per second). But for the players it will not be enough.
Version 2.0 – perfect for UltraHD
HDMI 2.0 is free from any limitations. Keep in mind, however, the both devices must be equipped with a 2.0 version – otherwise the transfer will always be automatically adjusted to the slower one.
DisplayPort
In this case it is also all about the specification. It was created back in 2006 and till that time it evolved creating few specification versions.
Version 1.1a – not enough
Depending on the amount of signal lines used (from 1 to 4) has a transfer from 1.6 to 10,8Gb/s which is not enough to transfer video in UltraHD.
Version 1.2 – 30 Hz in SST, no restrictions in MST
This and newer versions allow you to view the video in full 4K resolution 3840 x 2160. But to enjoy the UltraHD image with a frequency of 60 Hz and expanded 30-bit color spectrum both devices must support and have enabled Multi-Stream Transport (MST). All 4K monitors with DisplayPort port offer MST but sometimes you need to turn this mode manually from their menu. It is important to make sure the graphics card on the computer side supports MST – if not, you will fall back to Single Stream Transport (SST) with max freq of 30 Hz which is enough to work on static materials such as documents or spreadsheets. Also enough to watch movies at a resolution of UltraHD (most movies use 24/25 frames per second). But for the players it will not be enough.
VGA
As for VGA since it’s analog it clearly does not meet minimum requirements for data transfer needed for Ultra HD. If someone says different – they are wrong – no doubt about it.
DVI
Problem with DVI might be that new 4K monitors will not have this port available, only HDMI or/and DisplayPort. You could use converter and if you are lucky you might get only Full HD resolution. Better is to invest in new hardware.
Cables quality
A lot of people do not understand the difference between cables that cost $10 and the ones that cost $100. Remember that both DisplayPort and HDMI are digital interfaces, so the only difference is in the price of the cable. All currently available HDMI cables are “High Speed Category 2”. “Standard Category 1”, which actually may be too weak for 4K monitors, are nearly gone from the market.
Of course there might be a quality difference between very cheap and very expensive cables in the product itself, but as long as the cable is not physically damaged – data transfer lines are ok – it does not really matter how expensive cable we will use .