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  • 4KTVBlog - Tuesday, September 16, 2014 - link

    "Alternatively the additional bandwidth can be used to drive a single 4K@60Hz monitor at higher bit depths, such as 30bit and 36bit color."

    DP 1.2 already supports a single 4K@60Hz monitor with 30bit color. You don't need DP 1.3 for that.
  • Mondozai - Tuesday, September 16, 2014 - link

    Not on a single stream.
  • mczak - Tuesday, September 16, 2014 - link

    MST doesn't increase your bandwidth a single bit (quite the contrary, I suspect there's quite a bit more overhead). Thus, the OP is near certainly right. Now if some monitor can actually do it is of course a different question...
  • lordmocha - Tuesday, October 6, 2015 - link


    So DisplayPort 1.2 has a bandwidth of 21.6Gbit/s with overhead and 17.28 Gbit/s without.

    So i should be able to run the LG 31MU97 a 4096x2160x30@60 right?

    4096 px, 2160 px, 60 Hz, 30 bit, aspect ratio 1.90, 15.93 Gbit/s.
    17.02 Gbit/s, CVT-R, 21.27 Gbit/s TMDS, Pixelclock 709.042 MHz.
    16.7 Gbit/s, CVT-R2, 20.87 Gbit/s TMDS, Pixelclock 695.714 MHz.

    Using this calclator: http://web.archive.org/web/20150303100410/http://e...
  • Kevin G - Tuesday, September 16, 2014 - link

    The lack of DSC is kind of surprising as that was going to be the big feature to enable 8K resolutions at 4:4:4. Still the reduction in sampling to 4:2:0 for 8K at 60 Hz is tolerable for media that is captured in 4:2:0 color space. I would have also liked to have seen 4:2:2 at 30 Hz as an option.
  • nathanddrews - Tuesday, September 16, 2014 - link

    It's odd because earlier reports from were that they were targeting so-called Super-HiVision 8K @ 120 Hz for DP1.3.

    So the big question is will the 980 and 390 support DP1.3 or has that opportunity passed? A 120Hz 4K monitor with G-Sync (or similar adaptive refresh) is what I need for my next upgrade!
  • extide - Tuesday, September 16, 2014 - link

    I would guess that the next gen nVidia stuff (28nm GM204) will NOT include DP 1.3, however, I don;t think we will see another big 28nm GPU from AMD, I would bet we will see 20nm from them for their next big one, and it will be a bit farther down the road, but a good chance of having DP 1.3. Then nVidia's 20nm chip (GM210? GVxx?) will probably have DP 1.3.
  • TiGr1982 - Tuesday, September 16, 2014 - link

    According to videocardz dot com, GTX 980 (GM204) do not support DP 1.3 (DP 1.2 only). HDMI 2.0 is supported, however. Nothing is revealed regarding the so called R9 390(X).
  • nathanddrews - Wednesday, September 17, 2014 - link

    Yeah, I saw that. Too bad. I guess I'll have to wait for the Maxwell refresh or the 390X, unless the 980 has some trick for MST 120Hz 4K that we don't know about - it does have many more DP ports now. I realize that 4K@120fps will obviously not be possible in newer games with all the eye candy, but fortunately I still play a lot of older games that would easily play up to (or exceed) 120fps at 4K. For everything else, variable refresh will eliminate stuttering and tearing.
  • sunbear - Tuesday, September 16, 2014 - link

    I can see why DSC might be useful for compressing the output from a graphics card, but generally the cables between a computer and monitor are short and bandwidth is sufficient even without compression.
    The problem that really needs solving is how to transmit 4K at 60fps over long cables such as the ones that you might install between a receiver located in a rack in a closet somewhere and a projector or wall mounted tv. Cable tv, bluray, etc is already compressed so it seems stupid to uncompress, then recompress with DSC before sending down the display port cable to the tv.
    It would be much better to reduce latency and skip DSC altogether by just sending the original compressed stream directly to the tv to decompress itself. The inventors of DSC seem to have completely missed this obvious solution to limit cable bandwidth.
  • ddriver - Tuesday, September 16, 2014 - link

    32.4 Gbps - that's some serious bandwidth. Wonder if DP can be modified for other data transfer, just imagine external GPUs you plug into on-board weak GPU, without the need of Intel's overprices TB.

    Oddly enough, TB incorporates DP, so it shouldn't be much of a stretch to mod DP for external GPUs and other peripherals which demand high bandwidth.
  • fokka - Tuesday, September 16, 2014 - link

    yes, but TB utilises pci-e, which (afaik) is what you need for external graphic solutions, so why not improve upon TB, which already stands at 20Gbit bidirectional.

    that said, while i'm sure you can get a nice graphics boost with a 20-30Gbit interface, that's still slow compared to a full pci-e3.0 x16 slot offering about five times the bandwidth.
  • MrSpadge - Tuesday, September 16, 2014 - link

    "so why not improve upon TB"

    Because TB requires 2 relatively large, power hungry and expensive chips from Intel for each connection. Not sure anyone can do it better at those transfer rates, but TB isn't cheap by design.
  • repoman27 - Wednesday, September 17, 2014 - link

    If we're honest, DP requires an even larger, more power hungry and expensive chip to drive a port with 4 simplex lanes operating at 5.4 Gbit/s—i.e. a GPU. Granted only a small part of that chip is dedicated to the display controllers and DisplayPort PHYs, and they are at least available from multiple vendors, but even the burliest AMD GPUs can only drive 6 ports, and only in a single direction, for a peak aggregate bandwidth of 103.68 Gbit/s.

    A $9.95, 4-channel Thunderbolt controller weighing in at 144 mm^2 with a TDP of 2.8 W, on the other hand, can pump 80 Gbit/s aggregate through its 2 ports. Thunderbolt *is* actually cheap by design given its level of performance.
  • SirKnobsworth - Tuesday, September 16, 2014 - link

    1) DockPort

    2) All of that bandwidth is in a single direction which limits it's usefulness for peripherals.
  • Mondozai - Tuesday, September 16, 2014 - link

    Not on a single stream.

    PS:

    That chart that VESA released is misleading, it gives the impression that the rate of progress is constant. In reality, VESA flubbed the last 5 years. They should've been out with 1.3 several years ago to keep going at the pace they went before.
  • repoman27 - Wednesday, September 17, 2014 - link

    Considering it's a chart intended to show the generational increases in DisplayPort bandwidth and not the increases as a function of time, it's not misleading at all. The year of release is listed underneath each revision more as an informational point, not as an axis label.

    And I wouldn't say VESA flubbed the last 5 years at all. AFAIK, we've yet to see a single display panel that can be driven by DP 1.2 HBR2 SST make it in to a shipping product, and they've already released DP 1.3.
  • ArtForz - Wednesday, September 17, 2014 - link

    "AFAIK, we've yet to see a single display panel that can be driven by DP 1.2 HBR2 SST make it in to a shipping product"
    Huh? The retail Samsung U28D590 on my desk isn't "a shipping product"?
  • repoman27 - Wednesday, September 17, 2014 - link

    It isn't capable of using SST to do UHD at 60 Hz. It uses MST and an internal MST hub to drive the panel as two tiles.
  • ArtForz - Wednesday, September 17, 2014 - link

    Please inform yourself before making incorrect statements of fact.
  • repoman27 - Wednesday, September 17, 2014 - link

    Why don't you look up the model number of the panel in your display and see what kind of interface it uses for the TCON before you do the same.
  • repoman27 - Thursday, September 18, 2014 - link

    I'm gonna go ahead and apologize here for being so snarky.

    The Samsung U28D590D does in fact support UHD @ 60 Hz via DP 1.2 SST. So too does the Asus PB287Q. Knowing that both of those were based on a rather popular Innolux 28" panel with an 8-lane V-by-One HS interface, I wrongly assumed that they would require MST internally. Since I haven't really been following the 4K / UHD display scene too closely the past few months, I didn't realize that there's finally a scaler available that can handle 4-lane DisplayPort 1.2 HBR2 input. I'd very much like to know more about this scaler and why we haven't seen more coverage of it. Who makes it? Is it even an ASIC or just an FPGA?

    There also happen to be 4K laptops from Toshiba, Lenovo and Asus available now that use the Sharp 15.6" panel that has a 4-lane eDP interface. So that makes 5 products total, all released in the past 6 months. Which brings me back to the original statement that you quoted, which I began with "AFAIK..."

    As far as I now know, we've only seen a single display panel and a lone scaler that can be driven by a 4-lane DP 1.2 HBR2 SST link make it in to shipping products.
  • ArtForz - Friday, September 19, 2014 - link

    Apology accepted, and I guess I should apologize for my rather condescending tone.
    I should really have mentioned the panel# and that the Samsung/Asus/AOC/... all use a recent Novatek scaler, unlike the earlier 28" Dell with the same panel.

    As far as I know that Novatek is an ASIC and is currently the only scaler capable of HBR2 and SST UHD@60 in a shipping monitor. If anyone has better info, feel free to correct me.

    I *think* Mstar also announced a scaler capable of single stream UHD over 4-lane HBR2 and can drive 2 and 4 tile panels (40"+ *VA UHD@60 monitor? Yes please!), but I can't for the life of me find any trace of that announcement now, so take this with a huge grain of salt.

    What's also interesting, there seem to be panels capable of UHD@120 already on the market, e.g. a 48" *VA from CMI with a 4-tile 16-lane v-by-one interface.
    So unless I'm missing something, that means we're "only" a scaler short of maxing out DP1.3 right now.
    Which to me sounds like something close to DP1.3 should have been out a while ago, so we'd have shipping GPUs capable of outputting to such a beastie now.
    But then, this isn't a ideal world, I'm not the king of VESA nor a display or GPU manufacturer, and there's likely good reasons why things took as long as they did.

    Though something keeps bugging me, why not just make DisplayPort wider?
    Looking at the AUX protocol, extending it to 8 or 16 lanes would be pretty straightforward to do in a backwards compatible fashion. Yes, you'd have to add new connectors and cables for the wider variants, and likely physical adapters and ..., but to me this sounds like a surmountable problem.

    Anyways, no hard feelings and glad you checked for yourself. It's rare to find someone who values accurate information over winning an argument on the internet ;)
  • cosmotic - Tuesday, September 16, 2014 - link

    What about 4k@120hz?
  • The-Fox - Tuesday, September 16, 2014 - link

    Should be doable as with 24bpp, the B/W needed is only ~22.25 Gbit/s
  • kyuu - Tuesday, September 16, 2014 - link

    Perhaps someone here can clue me in:

    The article mentions "Displayport Active-Sync" near the end. Is this synonymous or related to Freesync, or is that a totally different issue?
  • haukionkannel - Tuesday, September 16, 2014 - link

    Yep. Free sync is AMD adaptation of active-sync, so basically the same thing.
  • kyuu - Tuesday, September 16, 2014 - link

    Great, thanks for the response!
  • magnusmundus - Tuesday, September 16, 2014 - link

    I noticed that they compressed the x-axis on their bandwidth graph to make it look like increases have been linear. The slope for DP1.2 to DP1.3 is really a lot less than it appears.
  • repoman27 - Wednesday, September 17, 2014 - link

    Because it's a graph comparing generational increases in bandwidth, not annual. The line would be flat in between generations if it were drawn as a function of time, seeing as bandwidth only increases with specific releases.
  • Iketh - Wednesday, September 17, 2014 - link

    Not one mention of 4K @ 120HZ.... is that not important to anyone else?
  • p1esk - Thursday, September 18, 2014 - link

    Very important. As someone mentioned above, should be doable with 24bbp.
  • Antronman - Friday, September 19, 2014 - link

    The decline of Gsync begins before it has even caught on.

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