Comment by drivebyacct2 | Hacker News Reader

Comment by drivebyacct2 | Hacker News Reader

I have a Crossover 27Q (similar to this, probably sourced from the same place as other brands on ebay: Catleap, Shimian, wherever Monoprice is getting them, etc). Gorgeous minimalist metallic shell. Swivel display. Adjustable height. $375 from Ebay. Pixel perfect. I can't exaggerate how amazing these displays are. They're the same LG panels used in Apple Cinema displays at nearly a third of the cost. It's wonderful to be able to have three files up side-by-side in Sublime without feeling cramped and have a Terminal and VLC stuck to top.

So, yeah, if you're bummed about these not being available, there's tons on eBay, alibaba, etc.

A few other tips:

First, Intel HD4000 can drive these displays but it must be over DisplayPort. Yes, this means that my Macbook Air (2012) with the Apple Dual link DVI adapter works fine with it. However, my desktop with HD4000 mobo does not have DisplayPort so I'm now driving it with an NVIDIA GTX660 over Dual-link DVI.

Second, many of these displays output incorrect EDID information requiring that you manually modeset in Xorg to get it to work with Nvidia's proprietary drivers. (Nouvaeu seems to figure it out on it's own, but it's a bit of a dog at that resolution).

Third, most of these lack upscaling support meaning you must be able to output at its native resolution; no hooking an xbox up to one.

edit: Sorry to link downthread, but turtlebits stumbled upon one that might not have these limitations/faults: http://news.ycombinator.com/item?id=5040906 before anyone jumps on the ebay link below.

About the HDMI/DVI issues, heres an overview of my (possibly incorrect) understanding, for those wondering (Note the resolutions listed can be fudged a bit by messing with display rate, ie it may be possible to get a single link dvi to display 24401400 @ 33hz)

DVI-A/I/D Single link supports up to around 1920x1200

* DVI-I/D Dual Link supports 2560x1600+

* HDMI <=1.2 supports up to 1920x1200

* HDMI 1.3 supports up to 2560x1600

* HDMI 1.4 supports up to 4096×2160

* HDMI1.3 intro'd different category cables, cat1 and cat2 (Sometimes called 'High Speed'). cat2 supports the higher res.

HDMI and DVI Single Link are compatible (you can get simple adaptors and hdmi-dvi cables). Note, single link only, ie HDMI to DVI adapter connected to a dual link cable and display will be act like DVI Single Link

HDMI w/Type B connector and DVI Dual Link are compatible, however as far as I know there were no HDMI Type B products ever made.

So you cannot convert HDMI>DVI to achieve 2560x1600

* To get 2560x1600 over DVI, you need a dual link card, display and cable

* To get 2560x1600 over HDMI you need a card with a >1.3 port, display and a >1.3 cat2 cable.

* Additionally, regardless of the HDMI standard supported by your card, it may not be capable of outputting 2560x1600 (The presence of a display port or dual link DVI is a good indicator)

So in theory most modern setups should support 2560x1600 over HDMI. In practice not so much, a few problems:

* Some displays and adaptors may claim to support >1.3, or not specify the version, and actually be <1.3

* Some displays and adaptors may be >1.3 but limit what they will output or display.

* Some displays may be >1.3 but report a lower max resolution in their EDID. Bypassing this/setting a custom mode may work just fine.

* Even if you do manage to get everything working together, you may experience general instability and errors.

TL;DR avoid HDMI for high resolutions if you can, it'll save you a lot of hassle.

I don't doubt this info, it jives with what I know, but I know that HD4000 will not drive this display over HDMI on my friends mobo (which coincides with the other anecdotes I've seen).

Sorry I meant to include this about the HD4000, you're totally correct. It and it's 3rd gen sibling actually support HDMI1.4, but fall into the 'Some displays and adaptors may be >1.3 but limit what they will output or display.' category, unfortunately.

Here's my rudimentary/half forgotten understanding gleamed from the PCH datasheet and random internet browsing:

* HDMI/DVI both use TMDS and share the same encoding/formatting for video and control. The Intel chipsets defines 9 TMDS lines for a port which are identical/interchangeable between the HDMI/DVI ports: 3 Data pairs, 1 control pair and the hot plug detection.

* The 3 data pairs, the control/clock pair and the hotplug pin form the connections of a single link DVI-D connector.

* The DVI spec identifies the max pixel clock of a single link DVI connection as 165Mhz

* Higher pixel clock requires dual link, via an extra 3 data pairs, which are not defined by intel in the datasheet

* HDMI uses a single link connection, with 3 data pairs, control pair, and hotplug. (Except type B connections which were dual link, but never actually produced by anyone)

* HDMI <= 1.2 defined a maximum pixel clock of 165Mhz (same as DVI). So at this point the video and control data is compatible with DVI, same pins and max clock

* HDMI1.3 upped it to 340Mhz over a single link. Which is incompatible with DVI, which increased max res by adding more lines, rather than change the existing ones

This is where I make a bit of a leap: as far as I know, since the lanes used for HDMI/DVI are defined interchangeably, they are limited to a max clock of 165Mhz, the DVI maximum.

So even though these cards are listed as HDMI1.4, the video data produced is effectively maxed at DVI-D single link/HDMI<=1.2 compatible.

TL;DR again: the intel HD graphics (Specifically the HD4000 and HD2500, but assumably the earlier ones as well) are limited to single link DVI-D and the equivalent pixel clock over HDMI, effectively 1920x1200. DisplayPort does doesn't share this. If you have an Intel adaptor, and want >1920x1200, you're gunna want to use DisplayPort.

To add to this problem, some graphics cards (such as ATI/AMD's Eyefinity) only have two display clocks and cannot output over hdmi/dvi without a special active (non-passive) adapter.

If I can ask a few questions:

1) Are Ebay/alibaba retailers trustworthy? I'd hate to be shipped a lemon (assuming they even ship outside the US).

2) Why must it be DisplayPort? Doesn't it support HDMI/DVI?

1. I wasn't shipped a lemon, so I can't testify as to what happens if you get one. That having been said, the person I bought from had tons of 99.8% reputation and I swear, I have no idea how it go to my doorstep from China so quickly (custom stickers and all indicating it erally moved that fast).

2. I have no idea why HD4000 won't drive that 2560x1440 resolution over DVI/HDMI. I just know that HD4000 has that prowess to output it and I read somewhere that it only works over DisplayPort. So far, based on my HD4000 MBA and desktop, that seems to be true. I'll see if I can find you a source on that.

edit: This is not the exact same ebay listing, but is from the same person and is the same product that I purchased: http://www.ebay.com/itm/New-Crossover-27Q-LED-P-27-DVI-D-Dua...

edit2: Sources on the HDMI/DVI/DisplayPort discrepancy: http://communities.intel.com/message/160909#160909

Thanks for your reply. I just bought a new nVidia card (GTX 650 Ti) and it doesn't include a DisplayPort, so it looks like I'm out of luck on this :/

Thanks anyway!

To clarify, I am driving my display over Dual link DVI from my Nvidia GTX-660. The resolution limitation is specific to both the HD4000 + HDMI/DVI.

That ebay listing indicates that GTX 4xx's and 5xx's are supported. I would suspect yours will be fine.

Oh, I thought you meant that it was a limitation of the screen. That's a relief, then. I have currently had a 22" LG for a few years, it might be time to get a new screen!

Thank you for your help.

No, the HDMI spec is restricted in the resolutions that it supports, it's nothing to do with the HD4000, which could be a separate issue

HDMI 1.3 supports this resolution and there are numerous sources that indicate that the HD4000 will not drive a 2560x1440 resolution over a DVI port. Also, me and everyone else with a Dual link DVI port and HD4000 will tell you that it flatly doesn't work.

1. I bought mine from green-sum on Ebay, no problems and his feedback is pretty spotless.

2. the Catleap range takes Dual-link DVI, which requires the powered adapter for (I use Apple's one for the MBP, and bought an extra minidisplayport -> displayport adapter for my work laptop).

So will a cheap mini displayport -> DVI adapter like this: http://www.monoprice.com/products/product.asp?c_id=104&c...

not work for one of these displays, coupled with a Macbook Air (2012)?

That will not work. You, unfortunately, need the expensive USB powered/assisted adapter. (I have both. Had to buy the other to drive the high resolution.)

I bought Apple's dual link adapter (http://store.apple.com/au/product/MB571Z/A/mini-displayport-...) . Was on special at a local store. It's not without problems, particularly awaking from sleep sometimes leading to "static" image blur requiring reconnection of the adapter.

Odd, I bought the dual-link adapter from monoprice and I thought I got gypped when my wife's Yamakasi Catleap would wake from sleep that way. I guess mini-displayport is just flaky in general.

When that happens, you can just put the display to sleep instead, then wake it a second later. That fixes the problem for me at least. The standard keyboard shortcut to put all displays to sleep is Shift-Control-Media Eject (⏏)

  >> Are Ebay/alibaba retailers trustworthy?

I have had very good results buying from sellers with >99% rating. I have had fairly poor results with sellers having 98% rating or lower.

I think that most people don't give bad reviews even after a bad experience. You might expect a bad experience once out of 50 times with a seller having a 98% rating, but I have found it to happen much, much more often.

I am using a Potalion brand 27in IPS screen from eBay right now and I am very pleased with it. It arrived from Korea in a few days and it has been working flawlessly for about a year now. I payed under $300 shipped, which is pretty amazing, I think they have gone up just a bit since then. There are a few sites/forums/blog posts that compare them, here is one: http://www.swiftworld.net/2012/04/14/budget-korean-27-ips-mo...

To your second question, it's funny to me that my old Macbook Pro (2007) could drive it out of the box, as it had the large DualLink DVI port on the side. My newer Macbook Pro (2011) has to use Apple's Thunderbolt to DualLink DVI adapter, which works great, but is one more thing to think about.

I've got my Crossover 27Q a month ago from this seller: http://www.ebay.com/itm/CROSSOVER-27Q-LED-27-2560X1440-PC-Mo...

Fully working, no dead pixels, slightly non-uniform backlight (it could be seen only on black background). The display is really great for the price.

The only downside for me is glossy screen, but it seems there are no cheap 27'' korean matte displays.

Hmm, thank you. I thought about getting one, but I'm worried it's too materialistic. My current screen is fine, after all...

Reply on news.ycombinator.com