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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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  • IceDread - Tuesday, September 21, 2010 - link

    Good review, very good to keep at it with input lag, very important for me.

    This monitor would be the perfect one if it just would be 120Hz!

    I so would love an ips panel at 30" with 120Hz!!

  • FXi - Friday, September 24, 2010 - link

    Even if it had an HDMI connector it wouldn't go higher than 1920x1080. Check out other high res HP monitors that have HDMI. Dell is the same way. Despite HDMI "being able" to output higher resolutions, ALL PC monitor HDMI inputs only recognize as high as 1920x1200 and most only do 1920x1080. So don't wish for an HDMI port. It won't do you much good.

  • FXi - Friday, September 24, 2010 - link

    Since many folks debate the U2711 and the ZR30 and the U3008/3011, it would be interesting to see how things fall.

    As always, very disappointed the IPS hasn't YET managed after decades, to cure it's low contrast issues. Any TV owner will tell you that contrast and black level really make a display look fantastic and PC monitors are no different.

  • James5mith - Thursday, November 18, 2010 - link

    Just wondering if anyone else has been able to get this monitor working on a Mac Pro with Dual-Link DVI.

    It would seem that DisplayPort bypasses the issue, but Dual-Link DVI fails to display. The monitor shows that it is getting a signal, the backlight is active, but the screen is blank. The Mac Pro thinks that the monitor is active, and has extended the display to it, but you cannot see anything.

    Odd, issue, and I've confirmed that the display and cable work on other systems. It is just the Mac Pro that is having the issue. Wanted to use this as a replacement for a 30" ACD, but it looks like I'll be returning it instead.

  • Matrices - Friday, November 19, 2010 - link

    It is so strange that you should mention this. I just received my monitor today and it has this exact same problem - except that it's defective across the board (on Windows 7 and Vista systems). Same symptoms, though: lights up, recognized by Windows, but displays absolutely nothing using the DVI. Nvidia cards don't have DP so I can't figure out if it's just the port that's defective or what. Anyway, I'm returning it, obviously.

  • momofone - Friday, January 7, 2011 - link

    I have a Dell workstation with nVidia Quadro FX 4500 with dvi-d connectors and I have exactly the same issue - blank screen. Acts like something should be displayed, i.e. the backlight is active, but nothing, nada, totally blank.

    Shame. Looks like this monitor is incompatible with the FX series workstation cards. I can connect the Apple 30" ACD and it work fine though. Looks like I will have to think about another ACD.

  • eajohnson - Tuesday, December 7, 2010 - link

    I just bought a ZR30W last week and while it is performing well with no functional problems that I can see, the construction seems a little odd in that the panel is loose at the top (if I push very gently anywhere along the top of the panel, it can be pushed inward but stops after a few mm i.e. is not secured. Is this normal? Anyone know why it would be part of the design for it to be loose like that? At any of the other edges the panel appears to not be loose.

    I tried HP forums and calling HP tech support but they didn't seem to know, what I need is to find other owners that can try theirs and let me know if mine is normal or is defective.

  • SanFranShootr - Monday, January 3, 2011 - link

    I've read on some other sites that Mac owners who have the ZR30W are having screen flicker problems when they updated from 10.6.4 to 10.6.5.

    Does anyone know whether this 10.6.5 problem has been resolved?

  • Rohirm - Saturday, January 8, 2011 - link

    I have ZR30W connected via DP to Mac Pro Mid 2010 (HD5870). No problems here. Using OS X version 10.6.6

  • NetJunky - Sunday, February 6, 2011 - link

    I'm new on this website, but I have a question too. Will there be review of cheeper displays? Which one is better and why. Since I think, that not everyone can afford ZR30w.

    By the way, review was great. Very initeresting.
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