Dell P2715Q / P2415Q (3840x2160p, IPS, sRGB)

obug

Limp Gawd
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Dumb question that I don't think I've seen specifically asked, but why are these Professionals and not Ultrasharps? Is there a specific, hard reason for the difference between the two lines outside of something like warranty?

It's quite odd these aren't in the U category as they have the same warranty as the Ultrasharps and the viewing angles/color specs are as good as monitors like the U2713HM.

Sometimes the number of ports and features (e.g. built in USB 3.0 hub) are a differentiator, but even that doesn't seem the be the case this time.

Maybe Dell is shifting their product lines around a bit as 4K and 27" becomes more mainstream? Maybe we'll see some nice priced 32" 4K U Series soon :)

Or it could be something really pragmatic such as the percentage discounts they offer to large business purchases being different on P and U series.
 
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Color depth has nothing to do with color gamut.

As far as I can see, color depth seems to have a lot to do with color gamut, but of course I know they are not the same thing.

Follow me here, lets take a look at the specs

P2715Q: CIE1976 (103%) and CIE1931 (77%) and 1.07 billion colors (color depth)
U2413: CIE1976 (120%) and CIE1931 (103%) and 1.07 billion colors (color depth)

As they have the same color depth but different color gamut %, it means that although beeing able to display the same distinct numbers of colors, they can not show the same range/gamut of colors. But which colors can P2715Q display then?

As sRGB color space has 16.7 milion colors, what are the others 903 milions colors P2715Q is able to display as it can display 1.07 bilion colors? Are all those colors outside adobe RGB or any color gamut we might want to be able to see?

I am no expert on this matter. I am just trying to figure it out.

------------
UPDATE
------------

Got this from another forum. It might help us.

http://www.colorforums.com/viewtopic.php?t=225

>If the RGB color model is capable of 16.7 million colors, has anyone ever >calculated how many colors the average person's eye is capable of >perceiving?

a good question. The RGB color model, using 8 bits per channel, is capable of creating 16.7 million 'number combinations' but not that many colors...

>Any idea on how many colors exist in nature?
see below

>How large is the gamut of the eye to the number of colors in nature?

see, now I've got to get all philosophical. Colors don't exist in nature. They exist in our visual system. so....

number of colors in nature = number of colors we can see

and

number of colors we can see = number of colors in nature

>How many colors are in the SRGB color space?

Now THAT I can give you an answer for.

A few rough numbers for comparison: (all these values are in cubic CIELab)

Gamut of human color vision: 2.2 - 2.3 million colors
Gamut of G4 Powerbook: 518,733
Gamut of Apple HD Cinema Display: 928,189

so, even though each of the displays has 16.7 million addressable RGB values, the Apple HD Cinema Display can display almost 410,000 more colors. A significant difference to say the least. It could be argued that the PowerBook really only needs about 19 bits for its display - who wants to start an argument though?

A few more values for comparison.

sRGB = 909,800
Adobe RGB = 1,320,550
SWOP TR001 = 297,500
ISOcoated from ECI = 400,350

please note, all these values are very rough. They are best used only for broad comparisons.

The number of colours that can be represented on a display are mostly determined by the colors of the colorants (filters for LCD, phosphors for CRTs). The more saturated the colorants the larger the gamut and the more individual colors can be displayed.

So, although monitors can ADRESS (color depth) milions and even bilions colors, they can not actually DISPLAY (color gamut %) all of them. Is that correct? Problem solved or am I missing something?
 
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Henri108

Limp Gawd
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465
So what will this mean for the average person doing everything in sRGB?
Will one look better than the other looking only at the numbers?
I am on the edge of ordering the 27", but this is holding me back a little as I also edit thousands of pictures a week in sRGB.
 

lucidrenegade

Limp Gawd
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Nov 3, 2011
Messages
388
It's quite odd these aren't in the U category as they have the same warranty as the Ultrasharps and the viewing angles/color specs are as good as monitors like the U2713HM.

Sometimes the number of ports and features (e.g. built in USB 3.0 hub) are a differentiator, but even that doesn't seem the be the case this time.

Maybe Dell is shifting their product lines around a bit as 4K and 27" becomes more mainstream? Maybe we'll see some nice priced 32" 4K U Series soon :)

Or it could be something really pragmatic such as the percentage discounts they offer to large business purchases being different on P and U series.

The warranties of the P and U series are slightly different. The P series has a "no bright pixels" replacement policy, while he U series has a "no dead pixels" policy. In other words, if the P series has a pixel that's stuck "on", they will replace the monitor. If one is stuck "off", they won't. With the U series, they'll replace it no matter what.

I used to be that the Ultrasharp series also came factory pre-calibrated, but they are doing that with the P series (or at least with the P2715Q) now too.
 

lucidrenegade

Limp Gawd
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Yes i am running 4k 60hz out of the box no problem

I did not change the default display port option but yes its on DP 1.2

MST is OFF

I have a gtx 980 and no issues whatsoever.

It is a super bright display, that 350 rating is accurate.

Loving it so far.

Same here. Since it's factory calibrated, I just left everything at default, though I did turn off the auto switching in the Dell Display Manager app. It really bugged me how the monitor blanked out for a second or two when it switched color modes. I just left it set at standard.
 
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altano

n00b
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Aug 30, 2011
Messages
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I've been using my P2715Q, which just arrived, all day today. If anyone has any questions let me know, but the gist of it is that I love the monitor so far. I will be calibrating it tomorrow but to my untrained eye the colors look great out of the box.

I'm mildly surprised that the much higher pixel density over my previous 27" 1440p monitor is noticeable not just with text but also my photographs in Lightroom. In short, everything is a ton sharper.

Scaling doesn't seem to be a problem in Windows. At 150% scaling, the icons in Firefox look a little soft, and I had to upgrade to Sublime Text 3 to fix an issue with the text being super fuzzy, but so far those are the only issues I noticed. I'm now experimenting with 125% scaling, which gives me much more real estate but is perhaps pushing my eyesight a bit. I wish I could do ~135% scaling or something.

I also installed a Firefox plugin called NoSquint which allows me to set the default zoom of websites to 125% (on top of my OS scaling) which works well.
 

androsforever

Weaksauce
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Nov 23, 2013
Messages
112
As far as I can see, color depth seems to have a lot to do with color gamut, but of course I know they are not the same thing.

Follow me here, lets take a look at the specs

P2715Q: CIE1976 (103%) and CIE1931 (77%) and 1.07 billion colors (color depth)
U2413: CIE1976 (120%) and CIE1931 (103%) and 1.07 billion colors (color depth)

As they have the same color depth but different color gamut %, it means that although beeing able to display the same distinct numbers of colors, they can not show the same range/gamut of colors. But which colors can P2715Q display then?

As sRGB color space has 16.7 milion colors, what are the others 903 milions colors P2715Q is able to display as it can display 1.07 bilion colors? Are all those colors outside adobe RGB or any color gamut we might want to be able to see?

I am no expert on this matter. I am just trying to figure it out.

------------
UPDATE
------------

Got this from another forum. It might help us.

http://www.colorforums.com/viewtopic.php?t=225



So, although monitors can ADRESS (color depth) milions and even bilions colors, they can not actually DISPLAY (color gamut %) all of them. Is that correct? Problem solved or am I missing something?

I am waiting for an answer to this as well.
 
Joined
Dec 8, 2014
Messages
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There are some people on another forum helping us solve the puzzle

http://www.fredmiranda.com/forum/topic/1335088

Hi Alexis - I'll take my shot at explanation.

The color gamut and color depth really are totally different and should be thought of as unrelated.

Unfortunately display monitor companies while being technically accurate in gamut % there is so much variation in how they quote numbers they sometimes can be useless and in particular how Dell has quoted color gamut.

Without going in to details of the color gamut measurements and standards here are the basics for those two monitors.

The Dell P2715Q is basically equivalent to sRGB color gamut.
The Dell U2413 is basically equivalent to Adobe RGB color gamut

Using the CIE1976 Color Scale (recommended over CIE1931) for a better feel for percentage of color gamut

sRGB is about 33% of the human visual spectrum
Adobe RGB is about 40% of the human visual spectrum

That may sound bad yet that includes all sources of light natural and artificially generated (e.g. color lasers)

Possible a better way to compare how much of the color gamut is covered is to compare those color gamuts to "Pointers" gamut. This is a gamut that was created by collecting a huge sampling of colors that occur in nature. Comparing to Pointers gamut

sRGB is 70% if Pointers gamut
Adobe RGB is 80% of Pointers gamut

-------------------

Now for color depth. It has already been mentioned by previous postings in this thread that this is just how finely divided a specific gamut is broken into.

Using 8 bit data per color channel or 24 bits allows dividing up the color/tones of any given color space into 16,772,216 total compartments

Using 10 bit data per color channel or 30 bits total allows dividing up the color/tones of any given color space into 1.07 billion compartments.

Higher bits just allows more subtle changes or increments across the color space. So not a bigger color gamut (e.g. higher levels of perceived saturation), just more finely divided up into more subtle shades of color.

Now one more piece on the 10 bits. Getting 10 bit color per channel is a lot more than buying a monitor that has 10 bits. You must have besides such a supporting monitor, a 10 bit per channel graphics card, an application that will support 10 bit color, as well the OS must support 10 bit color. e.g. if you own a Mac you are out of luck because OSX presently only supports up to 8 bits no matter if you buy a monitor with 10 bit depth.

Now that does not sound cool and the marketing folks for the monitors don't advertise that fact.

Hope the above information helps out some.
 

obug

Limp Gawd
Joined
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Messages
147
The warranties of the P and U series are slightly different. The P series has a "no bright pixels" replacement policy, while he U series has a "no dead pixels" policy. In other words, if the P series has a pixel that's stuck "on", they will replace the monitor. If one is stuck "off", they won't. With the U series, they'll replace it no matter what.

I used to be that the Ultrasharp series also came factory pre-calibrated, but they are doing that with the P series (or at least with the P2715Q) now too.

Looking at the pages for the P2715Q and the U2715H and the footnotes associated with the warranties both seem to only discuss bright pixels. The page were made by marketing folks so it's possible the U2715H warranty not mentioning dead pixels is a mistake.

I'm not trying to contradict you - I'm just trying to understand why the P2715Q is not an Ultrasharp.
 

lucidrenegade

Limp Gawd
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Messages
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Looking at the pages for the P2715Q and the U2715H and the footnotes associated with the warranties both seem to only discuss bright pixels. The page were made by marketing folks so it's possible the U2715H warranty not mentioning dead pixels is a mistake.

I'm not trying to contradict you - I'm just trying to understand why the P2715Q is not an Ultrasharp.

Must have changed since I looked into it awhile back. This appears to be the latest:

http://www.dell.com/learn/us/en/04/campaigns/dell-premium-panel-guarantee
 
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Alexis, that post on fredmiranda.com is spot on.

The Dell UP2414Q is advertised as being 10 bit. But of course, this is not really true at all since it can only accept 8 bit RGB input as far as I know (I do not have an NVIDIA Quadro or similar card to test). The panel I believe is specified to be 8 bit + FRC - so dithering is applied to get those extra bits. The image being sent to the monitor is still 8 bits, so you're getting fake 10 bits being applied automatically to smooth out color transitions between pixels. This is a pretty common feature on some high-end TVs by the way.

I wouldn't obsess over it too much - as long as the monitor can reproduce every shade without banding then it is good.
 

Henri108

Limp Gawd
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465
I wish I could do ~135% scaling or something.

You can:
Control Panel\All Control Panel Items\Display
Then click 'custom sizing options'. You can dial it in up to 1% (sometimes even is unsharp and even number will be sharp).
 

lucidrenegade

Limp Gawd
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Can someone please tell me how the P2715Q looks playing games at 1080P scaled up to the full size of the monitor?

I tested a couple of games and they look good to me. Don't know if it would affect response times in FPS games, but I don't really care about those.
 

androsforever

Weaksauce
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I'm glad they're continuing to offer 4k at 24". I thought the UP2414Q was going to be a once-off. Now if only they could put a G-Sync module in one.

Exactly what I was thinking... if they can get Gsync on a 24 inch 4k ips like this then I'm sold. Buying it :D
 
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For anyone who has one, how is your colour uniformity? I have one (in Australia) and it's very good except for a prominent band of yellow discolouration right in the centre of the screen all the way from top to bottom and greenish discolouration around the edges. Planning to return it but not sure whether to try for a replacement or get something else.
 
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Hi

I have my P2715Q for a week now, and i noticed that when i look at the left and right very edge of the panel in a bit of an angle,they are not very good backlit. Can anyone confirm this? Its not a very big deal but still id like to know if maybe my unit has a defect.

I took a photo:

 
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For anyone who has one, how is your colour uniformity? I have one (in Australia) and it's very good except for a prominent band of yellow discolouration right in the centre of the screen all the way from top to bottom and greenish discolouration around the edges. Planning to return it but not sure whether to try for a replacement or get something else.

color uniformity is top notch on mine. Best ive ever seen on a Monitor. (and ive seen quite a lot) White is very even across the whole panel.
 

Comixbooks

Fully [H]
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I so want 4K but don't want the lower Frame Rates in Games so could I turn low frame Rates games like say I'm getting 19 in BF4 online I turn it to medium or Low what can I expect?
 

spugm1r3

[H]ard|Gawd
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@comixbooks... a very good reason to not bother with 4k. What's the point of an extreme resolution if all the textures you see end up looking like an old Super Nintendo? If you are going 4k with anything less than a 290x (preferably in crossfire) and you are intending to game, you are likely missing out on all the reasons it's worth getting.
 

Comixbooks

Fully [H]
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ok Thxs I see these videos on you tube and someone was Running a 295X2 and it was going under 60 quite a lot.

I guess I'll wait for the first best 1440P that isn't ROG Swift
 

lucidrenegade

Limp Gawd
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ok Thxs I see these videos on you tube and someone was Running a 295X2 and it was going under 60 quite a lot.

I guess I'll wait for the first best 1440P that isn't ROG Swift

Yeah, unless you're going to invest the $$ into 2 GTX 980 or similar, don't bother with 4k. Unless you only play DOTA 2 or something.
 
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Yeah, unless you're going to invest the $$ into 2 GTX 980 or similar, don't bother with 4k. Unless you only play DOTA 2 or something.

Or you are not buying this monitor just for games.

4K resolution is awesome for those who want to see high resolution images (my case)

But I will try Battlefied 4 and Skyrim when the monitor arrives :) , even if I need to adjust resolution x game quality, high instead of ultra may be enough for a Asus GTX 770? Maybe just World of Warcraft :)
 
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LuckyB

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Or you are not buying this monitor just for games.

4K resolution is awesome for those who want to see high resolution images (my case)

But I will try Battlefied 4 and Skyrim when the monitor arrives :) , even if I need to adjust resolution x game quality, high instead of ultra may be enough for a Asus GTX 770? Maybe just World of Warcraft :)

I got the P2715Q and have two R9 290. It is possible to play bf4 at 3840X2160. Everthing is ultra except effects quality which I have turned down to high and disabled MSAA ( you don't need it at that resolution )

99% of of the time, it stays at 60fps or higher

Gaming at 4k is simply amazing and of course, viewing images at that resolution is spectacular...you can't distinguish the pixels
 

xelan

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I'm having a nasty "image memory" effect on my Dell U2713HM. When a window with pure white elements left open intact for about 30 mins then after you close it and open something with a gray background, you can clearly see color shift at the same spot where old white elements were.

Could anyone with P2715Q please verify that you don't have it. I would be very gratefull.
 
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Why would you invest money into 2 GTX 980s when R9 295X2 is so much better with frame pacing and XDMA and is nearly 40% cheaper? :O

Correct

Also, 2 x R9 290X is cheaper than 1 x R9 295X2.

Update 1

2 x GTX 970 reach the same FPS as 1 x R9 295x2, but costs much less.

bf4_3840_2160.gif
 
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Sanguineus

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Correct

Also, 2 x R9 290X is cheaper than 1 x R9 295X2.

Update 1

2 x GTX 970 reach the same FPS as 1 x R9 295x2, but costs much less.

bf4_3840_2160.gif

The cheapest GTX970 I found costs $329, so $658 for SLI:

http://www.newegg.com/Product/Product.aspx?Item=N82E16814500362

Actually, the R9 295x2 costs roughly the same ($679.99):

http://www.amazon.com/VisionTek-Radeon-295X2-Video-Graphics/dp/B00K8AGZA6/ref=sr_1_3?ie=UTF8&qid=1418917061&sr=8-3&keywords=295x2&pebp=1418917069309

The cost of R9 290x is also $329, so $658 for CrossFire.
 

aitoribarra

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I'm very interested in the P2415Q. I've got another Dell 1920x1080 monitor - U2312HM - so nearly the same size.

I'd ideally like to run the P2415Q at 200% scaling and the other at 100% - which you can't do in Windows 8.1 - only set a % for all monitors, or use the auto scaling thing which in my experience with combining a 24" 1920x1200 with a 17" 1280x1024 - at nearly identical real PPI - didn't work well. As they are both Dell, and presumably Windows gets the PPI info from the monitor's EDID is, there a chance that it will work the way I want? Or a way to hack it?
 
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At ~$680 the R9 295X2 is much, much better than 2x970s. Hell if you follow the HardOCP review R9 295X2 blows away even the 2xGTX 980 which has dropped frames and microstuttering compared to 295X's frame pacing and XDMA.

Honestly if this wasn't a 700W furnace I would be using it, but otherwise you will get 90% of the performance when GM200/R9 390X come out in 225W formfactor.
 

altano

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Is anyone else experiencing an issue where all your windows get re-arranged/shrunk every time the monitor goes off, e.g. when the machine goes to sleep? It's not super annoying but I'd love a solution.
 

altano

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Actually I found my own solution but it involved changing a bunch of registry keys in a way I am not super confident won't break anything, but it seems to have worked perfectly. I got the info from this thread: https://social.technet.microsoft.co...69c2/turning-off-display-resizes-open-windows

The fix was to go to HKLM\SYSTEM\CurrentControlSet\Control\GraphicsDrivers\Configuration, find the key beginning with SIMULATED_****, and then change PrimSurfSize.cx, PrimSurfSize.cy, and Stride to match the values in one of the earlier 00 keys, f00, 870, and 3c00 respectively (which in decimal is just 3840, 2160, and 15360, something related to the resolution).
 
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Interesting hack - it doesn't seem to work for me though with my Dell UP2414Q. :(

Maybe it's because it uses MST...and I have multiple monitors too. Oh well.
 

Lava Lamp Freak

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Isn't that just a general problem with DisplayPort? It drops the handshake, 'disconnecting' the monitor, and windows reverts to a tiny 'safe' resolution, screwing up your windows and shuffling your icons in the process (will make some full screen programs shit themselves too). I've had that every time I've tried to use DP, so I always end up using DVI when available.

I've never had that happen, and I've used multiple DP displays over the last couple years.
 

LuckyB

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Is anyone else experiencing an issue where all your windows get re-arranged/shrunk every time the monitor goes off, e.g. when the machine goes to sleep? It's not super annoying but I'd love a solution.

Try disabling DDC/CI in the monitor's menu.Depending on the OS you're running, it may resolve the issue.
 
Joined
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Isn't that just a general problem with DisplayPort? It drops the handshake, 'disconnecting' the monitor, and windows reverts to a tiny 'safe' resolution, screwing up your windows and shuffling your icons in the process (will make some full screen programs shit themselves too). I've had that every time I've tried to use DP, so I always end up using DVI when available.

In theory, modifying the SIMULATE_* registry entries should let you modify the 'safe' resolution to be much larger - like 3840x2160. But it didn't work for me - probably because of MST. What happens when I turn off my 4K monitor then turn it on again, is that the windows get shoved into a 1920x1080 screen, instead of the 3840x2160 that I set in the registry. This might be a side-effect of MST (1920x2160x2), or I missed editing another display configuration registry entry that doesn't begin with "SIMULATED_*".

Oh well.
 

shuffle2

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Can anyone with the monitor confirm that the P2415Q itself is not using MST? As far as I know, it supports an output which turns the overall DP link into MST, but the monitor isn't using the MST hack internally (like the previous model).
I've searched around but I haven't seen any hard facts about it...

Edit: actually, some amazon review makes it seem like MST is still used internally if you use 60Hz refresh...sigh... :'(
Edit2: Is there a list of good SST 4K monitors somewhere?
Edit3: http://www.tonymacx86.com/graphics/149597-dell-p2415q-p2715q-4k-60hz-sst.html#post944924 User confirms SST @ 60Hz... :V /me buys
 
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