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Samsung And Viewsonic Power Draw

CCFL Versus LED: Is There A Downside To Going Green?
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The first thought that crossed our minds when testing the Samsung BX2350 was that it looked eerily similar to the Asus MS238H. At 100% brightness, the two are essentially indistinguishable. Given that there are only a handful of true panel manufacturers on the planet, we wouldn’t be surprised if both companies were using the same glass. With the BX2350 selling for $260 on Amazon as of this writing, and the MS238H floating around at $170, you can examine Samsung’s perks and see for yourself if they add up to a nearly $100 price premium.


LED
CCFL
CCFL
Monitor Test
Samsung SyncMaster BX2350
Samsung SyncMaster P2350
Viewsonic VG2428wm
Blank screen saver
29.2 W
46.2 W
40.7 W
Video, 100% brightness
28.5 W
45.0 W
39.8 W
Video, 75% brightness
24.6 W
37.6 W
26.6 W
Video, 50% brightness
20.8 W
31.1 W
22.3 W
White, 100% brightness
26.5 W
42.9 W
38.8 W
White, 75% brightness
22.7 W
35.7 W
25.7 W
White, 50% brightness
19.0 W
29.3 W
21.4 W
Black, 100% brightness
28.7 W
44.8 W
39.5 W
Black, 75% brightness
24.9 W
37.7 W
26.6 W
Black, 50% brightness
21.1 W
31.4 W
22.5 W


Similarly, the Samsung P2350 lines up very evenly with Asus' VW246. The Samsung pair is our best representation in this roundup of a typical old versus new tech match-up. The CCFL design clearly lags LED by 55% on total draw across all test scenarios. So, are Viewsonic’s claims of 50% savings typical of what we should expect from LED monitors in general? Absolutely. Our widest divergence from Samsung was 62%. Relatively speaking, that’s a massive advantage. If you’re saving 15 W per screen in a triple-head display that runs 15 hours per day at 12 cents per kilowatt-hour, that’s a $30 annual savings on your electricity bill. Over the life of the triple-head rig, you’ll likely save enough to pay for one of the monitors. That’s not bad, especially if the screen looks better than its CCFL alternative. But let’s not jump to conclusions just yet.

At this point, we had a chance to query an unnamed BenQ product manager about our power assumptions and findings so far. This is what we received in reply:

  1. Power savings of up to 80% sounds amazing, but you’re not going to get that from the LED backlighting alone. For most LED applications, we rarely see power saving benefits up to that much.
  2. CCFL structure efficiency is less than with LED circuits. For example, the efficiency of the “converter” for LED is around 90%, while the “inverter” for CCFL is around 80% to 85%. In other words, not only does LED contribute to power savings, but the structure of the power circuit does this, too.
  3. In reality, four-lamp CCFL consumes more power than LED, but for two lamps, it consumes similar power as LED. That is because of the contribution from optical film inside the two-lamp backlight unit.


As for Viewsonic, power results are in line with what we would now expect from a conventional CCFL display. In fact, the VG2428wm undercuts the Asus and Samsung CCFL options by a significant margin. So, while we can debate whether Viewsonic should have followed Dell with a two-lamp design, we’ll at least compliment the company for doing a better job than most with the four-lamp option it delivered.

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