LCDs, CRTs, and geese

Originally published 2003 in Atomic: Maximum Power Computing
Last modified 03-Dec-2011.


People like LCD monitors.

People are idiots.

The above two statements are not connected. Well, not necessarily. Liking LCD monitors does not make you an idiot.

If you drop several hundred bucks on a new monitor simply because you don't know to click your mouse seven times, though, then I think that you, yourself, will not think too highly of your own intelligence when you find out.

More on the mystic seven clicks in a moment (OK, OK, maybe as many as nine, depending on your Windows flavour). First, some perfectly sensible reasons why non-foolish people like LCDs.

If you want a monitor that takes up very little space, then an LCD screen beats the heck out of any CRT monitor. Old long-tube CRTs can be truly enormous, but even modern short-tube models take up a volume roughly equal to the cube of the size of their front face.

LCDs, in contrast, typically have a stand of modest dimensions, and a panel assembly that's only a few centimetres thick.

And they're light. If you have to carry your monitor around, you'll be much happier if it's an LCD.

LCDs use less power, too, though that's unlikely to be a major issue for people who aren't living in the sticks in a solar powered house, or setting up a computer in their camper-van, or something.

Sure, many CRTs consume an easy hundred watts more power than a similar-sized LCD; maybe even 200 watts more, for bigger and/or older models. But since the CRTs cost so much less in the first place, it balances out, at least as far as basic accounting goes (environment, schmenvironment). Every hundred Aussie dollars you save on the purchase price will pay for another hundred watts of electricity for a year, non-stop, at Australian power prices. As I write this, a reasonable "19 inch" CRT (with about an 18-inch-diagonal viewable screen area) costs $AU500 or so; a decent 17 inch LCD (which really does have a 17 inch viewable diagonal) won't give you change from $AU800, and is likely to only consume about 50 watts less. So that LCD will take around six years to pay for itself, if it lives that long.

Back in the differences-most-people-will-care-about category, LCDs have perfect geometry. Even "flat screen" CRT monitors suffer from the fact that the image is being painted on the screen by three beams of electrons, which are steered to the right spot by magnetic fields. Doing that accurately in the absence of external magnetic fields is hard enough; when external influences (from speaker magnets, electric motors, power wiring, other monitors...) get mixed in too, you need a hatful of geometry adjustments to get a reasonably square and level image on the screen.

LCDs don't have CRT screens' non-square arrangement of phosphor dots, on which pixels fall as they may; they have a square grid of actual hardware pixels, each one made out of three little subpixels (one red, one green, one blue). So they can't help but have perfect geometry all the time. You're never going to have to adjust "pincushion" or "trapezoid" on an LCD, and local magnetic interference won't make their image distort, wobble or pulse. You can kiss the frequently-ineffective "moire" adjustment goodbye, too.

There you go. Some valid reasons for liking LCDs.

Funnily enough, though, the reason why a lot of LCD-lovers say they're keen on their screens isn't listed above.

Apparently, LCDs are just plain nicer to look at.

That old CRT gave me eyestrain, they say. The new LCD doesn't, they say.

This makes me suspicious.

See, the image on even a top-class LCD monitor is, in some quantifiable ways, inferior to the image on a CRT.

Chief among the problems of LCDs is that they look washed out when you look down at them and too dark when you look up at them. It's an unavoidable consequence of the polariser-sandwich design they use. At normal viewing distances, your line of sight to the top and the bottom of an LCD screen is generally sufficiently angled for this effect to be noticeable.

LCDs' razor-sharp pixels also mean that they do, at best, a pretty ordinary job of displaying resolutions below their physical pixel number, and generally don't even try to display resolutions above their pixel number.

Oh, and some of the pixels won't work.

Well, strictly speaking, it's some of the subpixels that won't work, and they only probably won't work; some LCD panels are flawless. But stuck-on or stuck-off subpixels are allowed by even the big-name monitor manufacturers, as long as the defects aren't too noticeable (stuck-off is a lot less obvious than stuck-on, and stuck-on blue is worse than stuck-on green, which in turn is worse than stuck-on red).

These days it's common to find mass market 15 and 17 inch LCD screens with only one stuck subpixel, but you're still likely to have to sort through a few to find one that's flawless. Doing this may not make you popular with your local monitor retailer.

And then there's contrast ratio, the ratio of the darkest black a screen can display to the brightest white. CRT contrast ratio is enormous, because a CRT (with correctly set brightness) can display a black that's as dark as the un-illuminated screen. This is good. LCD contrast ratio is not nearly as good, because an LCD trying to display black has to try to stop all of the light from its always-on backlight from getting through its panel. No LCD can entirely manage this.

So there are viewing angle problems, and non-native-resolution problems, and the likelihood of a dud subpixel or three, and not-so-great contrast ratio, too.

Why the heck do so many people report just "feeling better" when they use an LCD?

My theory is that those people were just running their CRTs at the default 60Hz maximum compatibility refresh rate.

That's what I'm thinking.

No kidding.

I'm thinking this because, over and over and over, I sit down in front of someone else's Windows box, and say "Ick!", and immediately open Display Properties to set the refresh rate to something other than 60Hz. 60Hz is the standard refresh rate because it'll work with practically every monitor that hasn't died of old age, and many that have. It is not the standard refresh rate because it looks good.

Not everybody's computer has this problem, and it's certainly not just the propellorheads who know how to change the refresh rate. It's not a hard thing to learn, at least when you're just talking about the desktop refresh rate and not 3D mode.

But lots and lots of people don't do it. They may notice the nasty flickery display, but I suppose they just think it's normal for a CRT.

Maybe they set a good refresh rate at some point, but then Something Happened (fill in the random Windows-confusing event of your choice here), and Windows flopped back to 60Hz on the next boot, because suddenly it thought it had a Default Monitor, or whatever. It's eminently possible for a display driver subsystem that was set up properly once to get tied up in its own underpants and revert to 60Hz later on. It's not shameful to have screwed-up refresh rates, especially if they were perfectly all right yesterday and all you did today was turn the darn computer on with the monitor still powered off. And Lord knows it's still depressingly difficult to get modern PCs to use respectable refresh rates in 3D mode.

But lots of people have never even taken the first step towards setting their monitor up properly. It's not just the rampant 60Hz that makes me think this; it's also the fat black border I usually see around the image on the 60Hz screens, until I adjust the size settings.

So, whatever the reason, a depressing proportion of the world's Windows boxes have their display stuck at 60Hz. And staring at a 60Hz image will give you eyestrain. Maybe even a headache.

LCDs don't have a refresh rate, in the CRT sense. They've got pixel response time (often slow enough that high-frame-rate video, especially games, will blur somewhat; that's another great LCD feature right there), but they don't flicker at all. The response time tells you how quickly pixels can change colour, not how often the whole screen's refreshed.

This means that some Power User who can't get a regular monitor set up right may well think an LCD's the greatest thing ever.

Wow! No nasty flicker! Hurrah!

Part of me thinks that it can't be this simple. But I can't deny what I keep seeing. Most of the world's CRT screens can, at the resolution they're displaying, do better-than-nothing 72 or 75Hz, or quite-acceptable 85Hz, or even more. But an alarming percentage of the ones I clap eyes on are set to sixty gol-durned Hertz.

If you dig LCDs for some valid reason, then that's fine. I'm happy for you, really I am.

And people whose CRT monitors are trying to give them photosensitive epileptic seizures aren't necessarily schmucks. Setting the right refresh rate in Windows is pretty painfully obscure; it's generally easy if you know how, but it's not as if there's a new-Windows-install pop-up message that tells you all about it. Windows XP is better than previous Windows flavours at picking an un-excruciating starting resolution and refresh rate, but once you install the proper drivers for your shiny new graphics card and (frequently) also tell Windows what monitor you really have, rather than the "Plug and Play Monitor" it's detected, all bets are off.

Nonetheless, however; if you're buying a new $AU1000 screen just because you couldn't figure out the fewer-than-ten clicks needed to de-flickerise your CRT...

Well, then I think you might just be a little bit of a goose.

Other columns

Learning to love depreciation

Overclockers: Get in early!

Stuff I Hate

Why Macs annoy me

USB: It's worth what you pay

"Great product! Doesn't work!"

The virus I want to see

Lies, damned lies and marketing

Unconventional wisdom

How not to e-mail me

Dan's Quick Guide to Memory Effect, You Idiots

Your computer is not alive

What's the point of robot pets?

Learning from spam

Why it doesn't matter whether censorware works

The price of power

The CPU Cooler Snap Judgement Guide

Avoiding electrocution

Video memory mysteries

New ways to be wrong

Clearing the VR hurdles

Not So Super

Do you have a license for that Athlon?

Cool bananas

Getting rid of the disks

LCDs, CRTs, and geese

Filling up the laptop

IMAX computing

Digital couch potatoes, arise!

Invisible miracles

Those darn wires

Wossit cost, then?

PFC decoded

Cheap high-res TV: Forget it.


Dan Squints At The Future, Again

The programmable matter revolution

Sounding better

Reality Plus™!

I want my Tidy-Bot!

Less go, more show

In search of stupidity

It's SnitchCam time!

Power struggle

Speakers versus headphones

Getting paid to play

Hurdles on the upgrade path

Hatin' on lithium ion

Wanted: Cheap giant bit barrel

The screen you'll be using tomorrow

Cool gadget. Ten bucks.

Open Sesame!

Absolutely accurate predictions

The truth about everything

Burr walnut computing

Nothing new behind the lens

Do it yourself. Almost.

The quest for physicality

Tool time

Pretty PCs - the quest continues

The USB drive time bomb

Closer to quietness

Stuff You Should Want

The modular car

Dumb smart houses

Enough already with the megapixels

Inching toward the NAS of our dreams

Older than dirt

The Synthetics are coming


Game Over is nigh

The Embarrassingly Easy Case Mod

Dumb then, smart now

Fuel cells - are we there yet?

A PC full of magnets

Knowledge is weakness

One Laptop Per Me

The Land of Wind, Ghosts and Minimised Windows

Things that change, things that don't

Water power

Great interface disasters

Doughnut-shaped universes

Grease and hard drive change

Save me!

Impossible antenna, only $50!

I'm ready for my upgrade

The Great Apathetic Revolution

Protect the Wi-Fi wilderness!

Wi-Fi pirate radio

The benign botnet

Meet the new DRM, same as the old DRM

Your laptop is lying to you

Welcome to super-surveillance

Lemon-fresh power supplies


Internet washing machines, and magic rip-off boxes

GPGPU and the Law of New Features

Are you going to believe me, or your lying eyes?

We're all prisoners of game theory

I think I'm turning cyborg-ese, I really think so

Half an ounce of electrons

Next stop, clay tablets

A bold new computer metaphor

Won't someone PLEASE think of the hard drives?!

Alternate history

From aerial torpedoes to RoboCars

How fast is a hard drive? How long is a piece of string?

"In tonight's episode of Fallout 4..."

How hot is too hot?

Nerd Skill Number One

What'll be free next?

Out: Hot rods. In: Robots.

500 gig per second, if we don't get a flat

No spaceship? No sale.

The shifting goalposts of AI

Steal This Education

Next stop: Hardware piracy

A hundred years of EULAs

The triumph of niceness

The daily grind

Speed kings


Game crazy

Five trillion bits flying in loose formation

Cannibalise the corpses!

One-note NPCs

Big Brother is watching you play

Have you wasted enough time today?

The newt hits! You die...

Stuck in the foothills

A modest censorship proposal

In Praise of the Fisheye


The death of the manual

Of magic lanterns, and MMORPGs

When you have eliminated the impossible...

Welcome to dream-land

Welcome to my museum

Stomp, don't sprint!

Grinding myself down

Pathfinding to everywhere

A deadly mouse trap

If it looks random, it probably isn't

Identical voices and phantom swords


Socialised entertainment

Warfare. Aliens. Car crashes. ENTERTAINMENT!

On the h4xx0ring of p4sswordZ

Seeing past the normal

Science versus SoftRAM

Righteous bits

Random... ish... numbers

I get letters

Money for nothing

Of course you'd download a car. Or a gun!

A comforting lie

Give Dan some money!
(and no-one gets hurt)