HP LP3065: A new contender for the 30" throne
by Jarred Walton on March 22, 2007 7:00 AM EST- Posted in
- Displays
Response Times and Buffering
A topic that almost always comes up as a problem with LCDs is their slower response times relative to CRTs. There's no doubt that even the best LCDs still exhibit some slight pixel smearing, but the vast majority of users are okay with the level of performance we have available now. Image retention on your retinas also occurs to some extent, so even if you can completely eliminate the smearing effect at the display level you won't necessarily see a perfectly crisp transition.
Besides lag at the pixel level, there has also been discussion about a buffering lag that occurs within the LCD before the image is ever sent to the panel for output. This can be particularly noticeable on some HDTVs when connected to a computer, as HDTVs will often do a significant amount of image processing. Whether or not delays are caused by the internal circuitry or by the LCD crystal matrix taking a moment to align itself isn't really important; the end result is what matters, so a display that updates quicker is usually preferred, especially by gamers.
The Dell 2407WFP and Gateway FPD2485W LCDs advertise 16ms TrTf and 6ms GTG response times. The older Dell 2405FPW comes with a 12ms TrTf and 16ms GTG response time, which is sort of the opposite of what we see on most current displays. The 3007WFP lists 14ms TrTf and 11ms GTG, while the newer 3007WFPHC and the HP LP3065 rate 12ms TrTf and 8ms GTG response times. The Acer AL2216W comes with the fastest advertised response time of the displays we've tested so far, boasting a 5ms GTG response time, but it doesn't explicitly state a TrTf value. There are of course other LCDs that are rated even faster, and ratings aren't always accurate, so let's see how these displays compare in practical use.
We used the Dell 2407WFP as the "baseline" display, so it is on the left in all of the following images. We then started the first game demo from 3DMark03 and took numerous pictures, after which we selected several representing the best and worst case results that we could find. With all of the LCDs running a 60 Hz refresh rate, new frames are sent to the display every 0.017 seconds, so that's our granularity. Pay attention to the value of the Time field in the following screenshots, as that will show whether the two displays are showing the same frame or not. Results for the other displays are available at the following links:
Acer AL2216W #1 Acer AL2216W #2
Dell 2405FPW #1 Dell 2405FPW #2
Dell 3007WFP #1 Dell 3007WFP #2
Gateway FPD2485W #1
Despite having the highest rated response times, the Acer AL2216W display actually appears slightly worse than most of the other displays in terms of response times. Internal lag, on the other hand, puts the Acer display at the top of the list, followed closely by both 30" displays. Between the two 30" displays, the LP3065 appears to suffer from less internal lag, consistently running about one frame ahead of the 2407WFP. However, pixel lag appears to be slightly worse on the LP3065, and there are several images where we can see very clear transitions.
Having said that, we never noticed any problems with pixel smearing during subjective testing, and it was only when we resorted to using a camera that we could capture the slight differences between the displays. It's entirely possible that we're getting old so that our eyes aren't bothered by a difference of 0.017 seconds. We strongly feel that most people won't have a problem with the slight image smearing that occurs on these LCDs, but this is something that will vary by individual. If you know you are bothered by image smearing, try out a display in person to see if it's suitable for your needs.
A topic that almost always comes up as a problem with LCDs is their slower response times relative to CRTs. There's no doubt that even the best LCDs still exhibit some slight pixel smearing, but the vast majority of users are okay with the level of performance we have available now. Image retention on your retinas also occurs to some extent, so even if you can completely eliminate the smearing effect at the display level you won't necessarily see a perfectly crisp transition.
Besides lag at the pixel level, there has also been discussion about a buffering lag that occurs within the LCD before the image is ever sent to the panel for output. This can be particularly noticeable on some HDTVs when connected to a computer, as HDTVs will often do a significant amount of image processing. Whether or not delays are caused by the internal circuitry or by the LCD crystal matrix taking a moment to align itself isn't really important; the end result is what matters, so a display that updates quicker is usually preferred, especially by gamers.
The Dell 2407WFP and Gateway FPD2485W LCDs advertise 16ms TrTf and 6ms GTG response times. The older Dell 2405FPW comes with a 12ms TrTf and 16ms GTG response time, which is sort of the opposite of what we see on most current displays. The 3007WFP lists 14ms TrTf and 11ms GTG, while the newer 3007WFPHC and the HP LP3065 rate 12ms TrTf and 8ms GTG response times. The Acer AL2216W comes with the fastest advertised response time of the displays we've tested so far, boasting a 5ms GTG response time, but it doesn't explicitly state a TrTf value. There are of course other LCDs that are rated even faster, and ratings aren't always accurate, so let's see how these displays compare in practical use.
We used the Dell 2407WFP as the "baseline" display, so it is on the left in all of the following images. We then started the first game demo from 3DMark03 and took numerous pictures, after which we selected several representing the best and worst case results that we could find. With all of the LCDs running a 60 Hz refresh rate, new frames are sent to the display every 0.017 seconds, so that's our granularity. Pay attention to the value of the Time field in the following screenshots, as that will show whether the two displays are showing the same frame or not. Results for the other displays are available at the following links:
Acer AL2216W #1 Acer AL2216W #2
Dell 2405FPW #1 Dell 2405FPW #2
Dell 3007WFP #1 Dell 3007WFP #2
Gateway FPD2485W #1
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| HP LP3065 |
Despite having the highest rated response times, the Acer AL2216W display actually appears slightly worse than most of the other displays in terms of response times. Internal lag, on the other hand, puts the Acer display at the top of the list, followed closely by both 30" displays. Between the two 30" displays, the LP3065 appears to suffer from less internal lag, consistently running about one frame ahead of the 2407WFP. However, pixel lag appears to be slightly worse on the LP3065, and there are several images where we can see very clear transitions.
Having said that, we never noticed any problems with pixel smearing during subjective testing, and it was only when we resorted to using a camera that we could capture the slight differences between the displays. It's entirely possible that we're getting old so that our eyes aren't bothered by a difference of 0.017 seconds. We strongly feel that most people won't have a problem with the slight image smearing that occurs on these LCDs, but this is something that will vary by individual. If you know you are bothered by image smearing, try out a display in person to see if it's suitable for your needs.
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lawrenpx - Saturday, December 4, 2010 - link
Has anyone been able to get the Matrox TripleHead2Go Digital to work with the HP LP3065 in either Linux Redhat or PC Windows? When I connect my monitors all I get is a blinking green light on the monitor which I believe means no signal. Perhaps I need to get a Linux driver but I can't find any. ThanksKeithP - Thursday, March 22, 2007 - link
While I understand some people can't wait for technology, it seems we are pretty close to seeing 120Hz refresh rates and LED backlighting. Given that, I think spending a bunch of money on a large LCD display may not be the best move.Of course, if you can't wait, the HP and Dell seem pretty nice.
JarredWalton - Thursday, March 22, 2007 - link
120Hz refresh rates will require something other than dual-link DVI in order to function. Right now, it's a matter of bandwidth. DVI runs at 165 MHz, which means that single-link maxes out at around 1920x1200 and dual-link maxes out at twice that (3840x2400). It will hopefully happen at some point, but we need a new input standard that provides more bandwidth first.chizow - Thursday, March 22, 2007 - link
Thanks for including an input lag comparison Jarred. Another suggestion to test is something I saw done by just an average user. He found a website or program that simply had an atomic clock or something that displayed current time down to the millisecond. Then he just used that to capture his comparison ISO from a digital camera. Essentially it gave him the exact difference in milliseconds between each panel without having to calculate the difference based on frame rates or discounting partial frames etc.The additional DVI inputs on the HP are nice though and hopefully your suggestions about future inputs are implemented in future 30" panels. One question though about the different inputs and resulting display resolutions. Are you able to control panel resolution using the panel itself? Or is that all controlled by the input device? I'd like to know if non-2560 input resolutions are upscaled to 2560 or if the panel displays them 1:1 with black bars. I know for PC inputs this should work with all Nvidia cards, but if you connected a PS3 via HDMI > DVI converter what display resolution would you get?
chizow - Thursday, March 22, 2007 - link
Thought about this some more. Would you get a corrupted display since the PS3 output isn't dual-link? Would be kind of a bummer but it makes sense.......Chucko - Thursday, March 22, 2007 - link
Amen on getting stuff reviewed sooner, this monitor has been out forever. Thanks for the review, great job!JarredWalton - Thursday, March 22, 2007 - link
It takes time to get products, especially when you're (re)launching a segment. The display began shipping in quantity around December, so it's been about three months. "Forever"? Possibly for some markets, but the fact is nothing new has come out in the 30" LCD market after this launch, and it's still good to have results in for future reviews. Hopefully I will be able to get earlier releases on future displays. :)JarredWalton - Thursday, March 22, 2007 - link
Forgot to say that when using a single-link DVI connection (which is what the PS3 uses), there was display corruption - or even a blank screen - up until Windows loaded. I booted - or tried to boot - a PC with Linux (again on a single-link connection). I didn't get any signal at all. It might be possible to get it to work if you set up Linux on a different display and then after configuring X for 1280x800 switch to the LP3065, but basically HP doesn't officially support single-link DVI. I would venture to say that a PS3 wouldn't work at all with the display... or an Xbox 360 or anything else that doesn't support 2560x1600 or possibly 1280x800.Renoir - Thursday, March 22, 2007 - link
Single-link DVI would appear to be a bit of a grey area. Why would HP go to the hassle and expense of including an HDCP cryptorom and then not allow you to easily utilise it over a single-link. I say "easily" because although you suggest it's possible you haven't managed to get it working.Does this mean that the display can "scale" 1280x800 despite not having an actual scaler because it fits so easily into 2560x1600? Stupid question maybe but just wanna make sure I understand what was meant by that.
AFAIK the ICT only affects the analogue outputs and High def dvd versions of powerdvd etc require HDCP on any digital outputs.
This issue is clear as mud. Would be great if you could find out what the deal is with HDCP content on this display!
JarredWalton - Friday, March 23, 2007 - link
I don't have any Blu-ray or HD-DVD drives, so I haven't been able to test. Given that HDCP support is now available on a lot of monitors, it's reasonable to say that older DVI ports don't support it, so ICT would affect them. The whole HDCP + Dual-link is this messed up area, as HDCP was originally created for HDMI and single-link.Of course, my technical opinion is that HDCP is just a joke and a waste of time and money anyway. Gee, how long did it take for people to figure out a way to decrypt Blu-ray and HD-DVD content? Thank goodness we all "need" HDCP cards and such now!
As for the 1280x800 support, the monitor fills the screen with content, but it's just a straight doubling of pixels. The Dell 3007 does the same thing. I guess that was easy enough to implement without any special hardware. All other scaling... well, there isn't any in the monitor. The GPU handles scaling (I recommend NVIDIA *strongly* here, as the ATI scaling is not quite as full-featured).
Anyway, I should be getting a laptop with a Blu-ray drive in the near future for review, so I'm going to hopefully be able to test dual-link plus Blu-ray output. Since no content currently uses ICT, though, it doesn't really matter. Frankly, if they ever enable ICT, a lot of people will be pissed.