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A New 30" Contender: HP ZR30w Review

 by Brian Klug on June 1, 2010 6:30 PM EST
95 Comments | Add A Comment
95 Comments

Display Lag and Response Time

For gamers, display lag is a very real concern, and display processing is a nebulously reported (if at all) specification for just about all LCD displays. We’ve been over this before, but ultimately, what matters isn’t GTG, full on, full off pixel response times, or what’s reported on the spec sheet, but the holistic latency of the monitor compared to something we can all agree is lag-free. We previously used a baseline LCD and compared with it as our benchmark of no display lag. Previously we were using a 17” Princeton CRT - some of you were a bit underwhelmed by that monitor.

I spent some time visiting (I kid you not) almost every thrift store in town, and found myself a veritable cornucopia of uh... lovingly cared for CRTs to choose from. I settled on a much more modern looking Sony G520 20” CRT supporting a higher resolution and refresh rate. It’s still not what I’m ultimately looking for, but it’s better. Oh, and it cost a whopping $9. ;)

I had to take another trip back in time to get this CRT... Well, almost.
 
To do these tests, we connect the CRT up to a DVI to VGA adapter on our test computer’s ATI Radeon HD5870, and the LCD panel under test to DVI using an HDMI to DVI cable. I debated for some time the merits of using the same VGA signal, however, what really matters here is how the two display methods matter in the way that you, readers, are most likely to set things up. In addition, using the VGA input on any LCD is bound to add additional lag, as this is definitely a hardware scaler operation to go from analog to digital signaling, compared to the entirely digital DVI datapath. The most optimal resolution common to the LCD and CRT was 1280x800.
 
We use the same 3Dmark03 Wings of Fury benchmark on constant loop, take a bunch of photos with a fast camera (in this case, a Nikon D80 with a 17-50mm F/2.8) with wide open aperture for fast shutter speeds, in this case up to 1/800 of a second. Any differences on the demo clock will be our processing lag, and we’ll still get a good feel for how much pixel response lag there is on the LCD.

As I mentioned earlier, the only downside is that this means our old data is no longer a valid reference.

To compute the processing lag, I do two things. First, I watch for differences in the clock between the CRT and LCD, noting these whenever they are visible. I did this for 10 captures of the same sequence. Second, one can compute the processing difference by taking into account the FPS and the frame number difference.
 
 
Of course, not every one of those frames is written to the display, but we can still glean how much time difference there is between these respective frames with much more precision than from averaging the time, which only reports down to 1/100ths of a second.

Traditionally IPS panels are a bit slower (for whatever reason) than cheaper TN panels when it comes to refresh rate and processing lag. In this case, the ZR30w is a bit slower, but only by a few milliseconds, not the tens of milliseconds or perceptible lag that we’ve seen in the past. This is intriguing, it’s entirely possible HP’s omission of an OSD IC does make a difference.

We’re still evolving what we think the best way to measure processing lag is, and even using a CRT isn’t foolproof. In this case, I set the LCD and CRT refresh rates to 60 Hz so both in theory grab the same frame from the GPU’s framebuffer. In practice, it’s likely that they just aren’t, explaining the difference. As we process more LCDs, we’ll be able to tell, but the processing lag we’ve measured from all three monitors this far is totally acceptable.

I played a number of FPS titles and RTS games on the display, and never noticed any display processing lag or ghosting to speak of. If you’re going to use a 30” panel for gaming, the ZR30w seems to be just as good as any.
 
One trailing frame visible
 
LCD response and latency performance still isn’t technically at parity with CRTs, but you’d be hard pressed to tell the difference.

In the ghosting images I snapped, I usually only saw two frames. The dominant frame, and the preceding frame. This is very surprising, since we’re used to seeing three. But all throughout the images I snapped, only two frames are visible. This is very impressive panel response.
 
Analysis: Brightness Uniformity Analysis: Power Consumption
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  • Taft12 - Wednesday, June 2, 2010 - link

    http://accessories.dell.com/sna/products/Docking_S...

    $150 CAD - if that's a tough sell, how did you convince them to buy you a monitor that costs over $1000?!

  • theangryintern - Thursday, June 3, 2010 - link

    that's weird. We order docking stations with every single laptop we order. When people are in their office, they all want dual 22" displays.

  • DigitalFreak - Tuesday, June 1, 2010 - link

    I'm happy with my Dell U2410 and its HDMI, DVI x 2, Display Port, etc. inputs. :-)

  • ghitz - Wednesday, June 2, 2010 - link

    We're talking about 30" here!

  • thorr2 - Tuesday, June 1, 2010 - link

    I have the LG W3000H-Bn that I got from newegg. I am very happy with it although it is on the green side before calibration. It would be interesting to see a professional review of it to see how it compares to the others. It is definitely cheaper than a lot of the competition.

  • zsero - Tuesday, June 1, 2010 - link

    Sorry, but there is a big misunderstanding in this article:

    > I have no trouble believing that HP's claims about 1+ billion colors are totally accurate - you have to
    > see it in person to believe it. There are just some colors I'm used to not seeing represented very
    > well; reds and blues especially, and the photos that I have looked at are spectacular.

    Color gamut and the number of colors are totally different things!

    But what is _missing_ from the article is that:
    1. Using 24 bit color (8-bit per color) with a calibrated display profile you get visible banding.
    2. Using 30 bit color (10-bit per color) you can calibrate a monitor without visible banding.
    3. For 30 bit color you need DisplayPort and a professional graphics card + driver + OS + software support. For example newest professional Nvidia Quadro or Matrox cards, with a good combination of software and OS!
    4. What you have seen was less than 16 million colors, as you have used DVI and a calibrated output from a consumer graphics card.
    5. The billion color thing is nothing but the good sounding fact that 2^30 > billion (actually it's 1 billion, 73 million, 741 thousand and 824)

  • Brian Klug - Tuesday, June 1, 2010 - link

    I totally agree and I'm glad someone caught me ;) To be honest, I'm still a bit confused about the 32-bit color setting in windows in the display driver window and how that relates to the 30-bit claim. It would seem to me that 32-bit true color is indeed being driven, no? There's definitely no banding visible, at least from what I've scrutinized.

    I did space on trying DisplayPort though, I'm going to give that a shot in a second here and will probably update if I find something interesting! ;)

    Cheers,
    Brian

  • Brian Klug - Tuesday, June 1, 2010 - link

    I now follow completely what you mean. I tried using DisplayPort and DVI both to pass 10-bit Deep Color to the ZR30w, but apparently that feature isn't implemented on the ATI HD5870. I'm hoping to try it on a 2010 MBP, but it'll be some time before my miniDP to DP adapter arrives so I can test.

    Until then, I'm not entirely sure what the status is, but realize this is an important concern and chief feature of the ZR30w. I'm going to continue to investigate. Honestly, I don't expect the gamut to change that much, but it would indeed be interesting to see if 10-bit deep color does work as advertised. I might need a better workstation card. I'll update when I find out.

    Cheers and thanks!
    Brian

  • prof.yustas - Tuesday, June 1, 2010 - link

    Excellent. Thank you. In addition, it would be very useful to hear your take on the best 24-inch 16:10 (not 16:9) display out there, which is another way of asking for the DELL U2410 vs. HP ZR24w comparison.

  • Mr Perfect - Wednesday, June 2, 2010 - link

    http://www.tftcentral.co.uk/ has reviewed both, if you're interested.
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