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NVIDIA Kepler Cards Get HDMI 4K@60Hz Support (Kind Of)
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NVIDIA Kepler Cards Get HDMI 4K@60Hz Support (Kind Of)

An interesting feature has turned up in NVIDIA’s latest drivers: the ability to drive certain displays over HDMI at 4K@60Hz. This is a feat that would typically require HDMI 2.0 – a feature not available in any GPU shipping thus far – so to say it’s unexpected is a bit of an understatement. However as it turns out the situation is not quite cut & dry as it first appears, so there is a notable catch.

First discovered by users, including AT Forums user saeedkunna, when Kepler based video cards using NVIDIA’s R340 drivers are paired up with very recent 4K TVs, they gain the ability to output to those displays at 4K@60Hz over HDMI 1.4. These setups were previously limited to 4K@30Hz due to HDMI bandwidth availability, and while those limitations haven’t gone anywhere, TV manufacturers and now NVIDIA have implemented an interesting workaround for these limitations that teeters between clever and awful.

Lacking the available bandwidth to fully support 4K@60Hz until the arrival of HDMI 2.0, the latest crop of 4K TVs such as the Sony XBR 55X900A and Samsung UE40HU6900 have implemented what amounts to a lower image quality mode that allows for a 4K@60Hz signal to fit within HDMI 1.4’s 8.16Gbps bandwidth limit. To accomplish this, manufacturers are making use of chroma subsampling to reduce the amount of chroma (color) data that needs to be transmitted, thereby freeing up enough bandwidth to increase the image resolution from 1080p to 4K.


An example of a current generation 4K TV: Sony’s XBR 55X900A

Specifically, manufacturers are making use of Y’CbCr 4:2:0 subsampling, a lower quality sampling mode that requires ¼ the color information of regular Y’CbCr 4:4:4 sampling or RGB sampling. By using this sampling mode manufacturers are able to transmit an image that utilizes full resolution luma (brightness) but a fraction of the chroma resolution, allowing manufacturers to achieve the necessary bandwidth savings.


Wikipedia: diagram on chroma subsampling

The use of chroma subsampling is as old as color television itself, however the use of it in this fashion is uncommon. Most HDMI PC-to-TV setups to date use RGB or 4:4:4 sampling, both of which are full resolution and functionally lossless. 4:2:0 sampling on the other hand is not normally used for the last stage of transmission between source and sink devices – in fact HDMI didn’t even officially support it until recently – and is instead used in the storage of source material itself, be it Blu-Ray discs, TV broadcasts, or streaming videos.

Perceptually 4:2:0 is an efficient way to throw out unnecessary data, making it a good way to pack video, but at the end of the day it’s still ¼ the color information of a full resolution image. Since video sources are already 4:2:0 this ends up being a clever way to transmit video to a TV, as at the most basic level a higher quality mode would be redundant (post-processing aside). But while this works well for video it also only works well for video; for desktop workloads it significantly degrades the image as the color information needed to drive subpixel-accurate text and GUIs is lost.

In any case, with 4:2:0 4K TVs already on the market, NVIDIA has confirmed that they are enabling 4:2:0 4K output on Kepler cards with their R340 drivers. What this means is that Kepler cards can drive 4:2:0 4K TVs at 60Hz today, but they are doing so in a manner that’s only useful for video. For HTPCs this ends up being a good compromise and as far as we can gather this is a clever move on NVIDIA’s part. But for anyone who is seeing the news of NVIDIA supporting 4K@60Hz over HDMI and hoping to use a TV as a desktop monitor, this will still come up short. Until the next generation of video cards and TVs hit the market with full HDMI 2.0 support (4:4:4 and/or RGB), DisplayPort 1.2 will remain the only way to transmit a full resolution 4K image.

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HP ZBook 14 Review: Mobile Workstation Meets Ultrabook

What do you get when you cross an Ultrabook with enterprise features including an optional professional OpenGL GPU? This is apparently the question HP’s engineers were asking, and the result is the ZBook 14. We haven’t seen many Ultrabooks with discrete graphics so far, which isn’t too surprising considering the thin chassis designs and the need to keep everything running cool. Needless to say, if you’re hoping for a high-end GPU in an Ultrabook, that’s not happening right now, but HP has included an AMD FirePro M4100 FireGL V graphics solution, an entry-level dGPU solution, but as a member of the FirePro family it comes with drivers that have a few extra features unlocked. If you want a thin and light laptop (Ultrabook) but still want access to a professional level GPU, this is basically the only option right now. Read on for our full review.

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HP ZBook 14 Review: Mobile Workstation Meets Ultrabook

What do you get when you cross an Ultrabook with enterprise features including an optional professional OpenGL GPU? This is apparently the question HP’s engineers were asking, and the result is the ZBook 14. We haven’t seen many Ultrabooks with discrete graphics so far, which isn’t too surprising considering the thin chassis designs and the need to keep everything running cool. Needless to say, if you’re hoping for a high-end GPU in an Ultrabook, that’s not happening right now, but HP has included an AMD FirePro M4100 FireGL V graphics solution, an entry-level dGPU solution, but as a member of the FirePro family it comes with drivers that have a few extra features unlocked. If you want a thin and light laptop (Ultrabook) but still want access to a professional level GPU, this is basically the only option right now. Read on for our full review.

Samsung Launches the Galaxy S5 Broadband LTE-A: First Snapdragon 805 Phone, First 20nm Modem
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Samsung Launches the Galaxy S5 Broadband LTE-A: First Snapdragon 805 Phone, First 20nm Modem

While this launch is Korea-only, Samsung recently announced a new version of their Galaxy S5 smartphone, dubbed the Galaxy S5 Broadband LTE-A. Naming aside, this makes this phone the first to launch with APQ8084 and MDM9x35. For those unfamiliar with Snapdragon 805 and MDM9x35, this means that the CPUs are now Krait 450 instead of Krait 400, and the GPU is now Adreno 420 instead of Adreno 330. While the CPU revisions are minor, the GPU is fast enough to have the same level of performance at 1440p as an Adreno 330 at 1080p. The MDM9x35 modem also means that category 6 LTE is supported for speeds of up to 300 Mbps. The MDM9x35 is also the first 20nm SOC part shipping from TSMC, which bodes well for 20nm SoCs in the near future.

Qualcomm also notes that this phone integrates the WTR3925 transceiver, so carrier aggregation is done on a single chip instead of the WTR1625L/WFR1620 dual-chip solution that was previously needed. Samsung also integrated a QHD (2560×1440) OLED display into this model at the same 5.1″ display size. The only other difference is that the phone now has 3GB RAM instead of the 2GB present in the international model. Otherwise, the rest of the phone is identical to the international Galaxy S5. It’s curious to note that Samsung has chosen to use the 2.5 GHz bin of the APQ8084 line rather than the highest 2.7 GHz bin, although the reasons behind this decision aren’t quite clear yet.

Samsung Launches the Galaxy S5 Broadband LTE-A: First Snapdragon 805 Phone, First 20nm Modem
  • Comments are Closed

Samsung Launches the Galaxy S5 Broadband LTE-A: First Snapdragon 805 Phone, First 20nm Modem

While this launch is Korea-only, Samsung recently announced a new version of their Galaxy S5 smartphone, dubbed the Galaxy S5 Broadband LTE-A. Naming aside, this makes this phone the first to launch with APQ8084 and MDM9x35. For those unfamiliar with Snapdragon 805 and MDM9x35, this means that the CPUs are now Krait 450 instead of Krait 400, and the GPU is now Adreno 420 instead of Adreno 330. While the CPU revisions are minor, the GPU is fast enough to have the same level of performance at 1440p as an Adreno 330 at 1080p. The MDM9x35 modem also means that category 6 LTE is supported for speeds of up to 300 Mbps. The MDM9x35 is also the first 20nm SOC part shipping from TSMC, which bodes well for 20nm SoCs in the near future.

Qualcomm also notes that this phone integrates the WTR3925 transceiver, so carrier aggregation is done on a single chip instead of the WTR1625L/WFR1620 dual-chip solution that was previously needed. Samsung also integrated a QHD (2560×1440) OLED display into this model at the same 5.1″ display size. The only other difference is that the phone now has 3GB RAM instead of the 2GB present in the international model. Otherwise, the rest of the phone is identical to the international Galaxy S5. It’s curious to note that Samsung has chosen to use the 2.5 GHz bin of the APQ8084 line rather than the highest 2.7 GHz bin, although the reasons behind this decision aren’t quite clear yet.