What exactly is 4K? That is the question. At least, it’s the first question we need to address – and the answer isn’t altogether straightforward. It’s not as simple as defining, say, 1080p. That simply means 1,920 by 1,080 pixels, progressively scanned rather than interlaced. The end.
4K started out as a sort of high-end cinematographic standard, involving 4,096 x 2,160 pixels and a resulting odd 19:10 aspect ratio. And for some diehards, that’s what 4K is. Nothing more, nothing less. However, for PC monitors, the reality is that 4K involves 3,840 x 2,160 pixels in the standard 16:9 aspect ratio. As a result, the popular definition of 4K today boils down to a display with roughly 4,000 horizontal pixels.
The other way to look at 4K PC monitors is as four full 1080p displays on a single panel. That 3,840 x 2,160 pixel grid is precisely four 1080p grids arranged in two rows, one atop the other. So, yes, 4K PC monitors offer precisely four times the pixels of a bog standard 1080p panel.
Power up
Handily, that brings us to our first major sticking point when it comes to 4K on the PC – namely graphics power for 4K gaming. Running a 4K display is essentially the same as driving four 1080p screens at the same time. It’s a huge load on your graphics subsystem – and it’s currently debatable whether any single graphics card is fully capable of 4K gaming.
For an in-depth discussion of exactly what the implications are in terms of frame rates and the kind of graphics hardware you’ll need, see ‘The 4k gaming conundrum’ opposite. But if you don’t care to get bogged down in the finer points of technical aspects like anti-aliasing and non-native interpolation, suffice to say the bottom line is that installing multiple graphics cards might be a requirement, and that’s problematic for us. Even if you’re flexible about what constitute acceptable frame rates and game image quality settings, odds are you’ll at least need to buy a new graphics card.
Another related issue is display interface support. It’s surprising but true that not all versions of the DisplayPort interface fully support 4K. DisplayPort 1.1 will do 4K resolutions, but only at a refresh rate of 30Hz. Believe us when we tell you that a PC display running at 30 frames per second looks truly, deeply awful. This is surprising when you consider that feature films look fine at just 24 frames per second, but whatever the explanation in terms of physics and biology, the net result is simple: 4K only makes sense with minimum 60Hz support.
As for the HDMI and DVI options, the latter is basically a non-starter. For HDMI, it’s again a bit complicated. You could use a pair of existing HDMI connections to drive a 4K display as a pair of virtual screens. But that’s pretty clunky and can cause problems, especially in games. Ultimately, we’ll have to wait for HDMI 2.0 for proper 60Hz single-screen 4K support.
Right now, only DisplayPort 1.2 gets the job done properly. Regardless of the question of in-game frame rates, that’s what you’ll need from your graphics card just for a decent desktop experience. Once again, that may mean a new graphics card, adding significantly to the cost of making the move to 4K.
Pitch perfect
What else do you need to know about 4K? One critical consideration involves pixel pitch (the distance from the centre of one pixel, to the centre of its neighbour). However you slice it, 4K involves a preposterous number of pixels. Eight million, in fact. The result is a super-fine pixel pitch on desktop-sized displays. That’s part of the appeal of 4K, no question, but it also raises problems regards usability on the desktop. First up, Windows still doesn’t look great when you change the internal scaling option away from one-to-one or 100 per cent. Most elements of Windows itself work well enough, but third party apps including web browsers are often on the blurry side.
More generally, the web itself is based on bitmapped images and elements that look grotty when scaled – images, logos, banners and so on – so running at any scaled setting in Windows is far from ideal. How much of a problem that is depends on two things. Your eyesight and your tolerance for peering at tiny text are part of the mix, but screen size is even more of a factor.
Currently, 4K screens are available in sizes from 24 to 32 inches – so that’s precisely the same resolution painted across panels of very variable sizes. For us, the 24-inch option is out of the question. The pixel pitch is simply too small for practical use in Windows except for niche activities such as professional image editing. Move up to 28-inch displays and things are more marginal, but we think it will be just the wrong side of comfortable for most people. Step up again to a 32-inch screen and things make much more sense. Problem is, 32-inchers currently cost £2,000 and up, and that’s simply too rich for our blood. For most of us then, it probably boils down to the new generation of 28-inch 4K panels that start at a relatively reasonable £500.
Intriguingly, those screens are all based on ‘twisted nematic’ (TN) technology – one of the earliest forms of LCD. For many people, that will ring immediate alarm bells. But as you’ll see from our reviews, with these 4K monitors, TN tech has taken an enormous leap forward.
These are exciting times to be looking for a new monitor. 4K tech does have its limitations, but with prices tumbling and the technology maturing, it might be time to invest in a new screen that could last you the better part of the next decade.