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Asus Power Draw

CCFL Versus LED: Is There A Downside To Going Green?
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Let’s start by examining our Asus trio. To be honest, this article began many months ago with some considerable dialog between Asus and ourselves. The two MS-series monitors were the first units we tested, and it was with them that we devised our first power testing methodology.

Black and white screen tests are pretty self-explanatory; we used an empty MS Word 2003 document at full-screen with no toolbars showing to create the white display while full-screen back was done by having a Windows screen saver show only 100% black. For video testing, we ran a two-minute clip from “Sherlock Holmes” and took the average power draw value as measured by a Belkin Conserve energy monitor sitting between the display and the wall.


LED
CCFLCCFL
Monitor Test
Asus MS238H
Asus MS246H
Asus VW246
Blank screen saver
29.3 W
29.9 W
44.8 W
Video, 100% brightness
28.9 W
29.0 W
44.8 W
Video, 75% brightness
25.6 W
25.4 W
38.5 W
Video, 50% brightness
22.3 W
22.3 W
32.1 W
White, 100% brightness
27.7 W
27.2 W
43.8 W
White, 75% brightness
24.4 W
23.7 W
38.1 W
White, 50% brightness
21.2 W
20.6 W
31.4 W
Black, 100% brightness
28.9 W
29.1 W
44.3 W
Black, 75% brightness
25.6 W
25.6 W
38.4 W
Black, 50% brightness
22.4 W
22.5 W
32.0 W


The first thing that jumps out here is that the two MS models live up to their spec sheets’ promises of similar power consumption. Even if the vendor spec of a 33 W maximum proved pessimistic, the differences in draw in all of our scenarios are effectively nil. Yet one uses LED backlighting and the other CCFL. Huh?

We immediately sent these early results back to Asus' team, which reported that “the product manager is quite surprised also.” We suspected that the power circuitry must be the actual determiner of power consumption, and not the backlight technology. Further inquiry yielded this official reply: “Actually, [the product manager] was surprised that nobody had asked the question before now. Yes, the MS series uses the same electronics regardless of panel type, so their base energy consumption numbers will be the same.”

This bombshell was validated when we received the VW246 and confirmed that it indeed sucked down roughly 50% more energy than its CCFL-based cousin.

As for power numbers, another interesting point leaped off the spreadsheet. In retrospect, we should have guessed it all along, but so many years of using CRTs caused us never to question the assumption that black was better. Black saved energy. That’s why we have Blackl.com (yup, still running) for all those users who have Google Search as their home page. But in the LCD world, where LCD matrices must apply voltage in order to twist the crystals within a panel cell in order to block the backlight from shining through, black is bad. Black wastes energy. This is why a screen showing HD video usually consumes less energy than the same screen sitting at a black Windows desktop. Often, the most energy inefficient thing you can do is run a blank screen saver, that old power-saving standby from the CRT era. Things change.

As you can see, there’s a significant difference—30% to 40%—between running a screen at 100% brightness versus 50%. If you reach out to your display right now and dial back the brightness from 100% to 50%, it’ll probably look very gray and muddy to you. Most of us have become accustomed to 100% brightness, but that’s actually a lot like letting your car engine idle at higher RPMs. In reality, you’re not going to drive any faster; you’re just wasting gas.

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Top Comments
  • 15 Hide
    nevertell , May 2, 2011 4:23 AM
    How about doing this with IPS panels ? :>
Other Comments
  • 3 Hide
    Anonymous , May 2, 2011 4:11 AM
    In the "Wrapping It Up" section, perhaps you meant "LED" instead of "LCD"?
  • 15 Hide
    nevertell , May 2, 2011 4:23 AM
    How about doing this with IPS panels ? :>
  • -8 Hide
    nforce4max , May 2, 2011 4:46 AM
    I am going to get such a monitor later this year. Imagine the leap from CRT to Led LCD.
  • 9 Hide
    Ragnar-Kon , May 2, 2011 4:47 AM


    I personally can't wait until the OLEDs manufacturing process becomes cheaper. Having seen Sony's new OLED displays at this year's NAB in Vegas, I can say they are VERY VERY impressive.
  • 1 Hide
    scook9 , May 2, 2011 5:04 AM
    I know that I have been rocking a pair of Gateway FHD2400's for a few years now and love them as they meet all my needs and have never left me wanting
  • 1 Hide
    g00b , May 2, 2011 5:12 AM
    Ummm ... LED? They are all LCD :) .

    "Ultimately, we’d pick LCD for media consumption, but we’d pick CCFL for editing work where detail and accuracy are paramount. LCD is more fun to watch; CCFL is more reliable."
  • -2 Hide
    Anonymous , May 2, 2011 5:17 AM
    Please substitute "LCD" with "LED" everywhere in the conclusion section!
  • -4 Hide
    theshonen8899 , May 2, 2011 5:20 AM
    Basically the differences are very dramatic right? I'm gonna sound like a hippie for this but I'd definitely go for the greener option. Just being polite for our future generation is all.
  • -2 Hide
    Anonymous , May 2, 2011 5:22 AM
    what g00b said. At the end you start saying LCD instead of LED, might confuse some poor soul.
  • 6 Hide
    wrxchris , May 2, 2011 5:35 AM
    May not be too relevant here considering that this article was based around image quality, but as a gamer, I'm still plenty satisfied with my trio of 25.5" Asus TN monitors. Yes, they bleed a bit of light around the edges and the colors may not be very accurate, but they handle fast moving images with no problems and only cost $750 for the set. And my favorite feature is the 16x10 aspect ratio, which is becoming quite hard to find these days; not sure why people are so willing to give up vertical screen space.
  • 5 Hide
    haplo602 , May 2, 2011 5:48 AM
    still does not beat a high quality CRT in image reproduction. size/weight/power are another thing.
  • -9 Hide
    pirateboy , May 2, 2011 6:02 AM
    if you check the evidence of osama's death on a ccfl screen you would discover he isn't really dead but it's just some random bearded dude they shot
  • 4 Hide
    Kisakuku , May 2, 2011 6:40 AM
    X-Rite's iMatch software doesn't have a correction for LED backlighting. A colorimeter like i1 Display 2 is not a spectrophotometer and can't just measure any screen thrown at it. It requires corrections for LED and WCG-CCFL backlighting. Not sure how you can make far-going conclusions from these inaccurate measurements.
  • 8 Hide
    LuckyDucky7 , May 2, 2011 6:50 AM
    HOW ABOUT SOME CHEAP IPS SCREENS?

    It's starting to look bad- if you're spending 200+ dollars you might as well be buying a REAL screen instead of these ones.
    Even 40 more dollars buys you a screen FAR superior to these crappy TN panels.

    So why aren't they being reviewed?
  • 4 Hide
    g00ey , May 2, 2011 1:15 PM
    It would be interesting to look at which LED lit panels use local dimming and which ones do not.
  • 4 Hide
    masterbinky , May 2, 2011 2:09 PM
    The funny thing in the opening of the article, it typically isn't the CFL that goes out in monitors. It is the power inverter, that powers the CFL. When I did dell repairs, it's funny they didn't let you just get the inverter to replace, you had to replace the whole panel.
  • 3 Hide
    masterbinky , May 2, 2011 2:17 PM
    nforce4maxI am going to get such a monitor later this year. Imagine the leap from CRT to Led LCD.

    I image it's a leap off a cliff. You'll be dissapointed if you place them side by side. Well, depending on what your looking at, but try a dark image with detail in it,hint: you'll have to use the CRT to identify that image. Black crush sucks.
  • -4 Hide
    mcd023 , May 2, 2011 2:21 PM
    great article. thanks.
  • 4 Hide
    bildo123 , May 2, 2011 2:44 PM
    I was going to make the switch from a 24" VA panel to a newer LED panel (in which I tried two). The first was an Acer LED 23" and the blue hue this thing put off was gross. It didn't how much I calibrated it the colors were dull and the blue hue remained. The next LED I tried was the Samsung BX2450, 24"; the colors were better and the blue hue was less noticeable but it was still apparent (at least to me). I realize both are TN panels as well but I think I'll wait it out until a nice LED-IPS panel comes out for sale in the States.
  • -3 Hide
    haftarun8 , May 2, 2011 2:45 PM
    @ masterbinky Have you looked at top quality IPS panel LCD's calibrated compared to a CRT lately? The HP LP2475w at work beats out an old NEC Multisync 22" CRT with darker blacks even though the whites are brighter, has very accurate colors after calibrating, and has zero black or white crush - every shade of extreme blacks and whites can be discerned on test images. If you don't want crap for LCD's you still have to spend over $500 for your monitor, no getting around it.
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