The Skylake NUC hit the shelves some 6-7 weeks ago, but the lack of HDMI 2.0 port was a disappointment to many people looking forward to use the Skylake NUC as a HTPC. The full-size HDMI 1.4 port in the NUC can only support 4k resolutions at a maximum of 30 frames per second. However, there is also a DisplayPort 1.2 in the NUC that has enough bandwidth to support 4k at 60 frames per second. However, there are very few televisions with DisplayPort connectors on the market (why?).
DisplayPort 1.2 to HDMI 2.0 adapter seems like a good and easy solution, but there has been none on the market before! It doesn’t sound that complicated, but actually an adapter needs to have quite a bit of active electronics to convert DP 1.2 to HDMI 2.0 signal. Initially there were some DisplayPort to HDMI adapters that were marketed as enabling 4k with high refresh rates, but were actually not HDMI 2.0 compatible and thus they did not enable 60 Hz at 4k resolutions. Club 3D is one of the first manufacturers who have been able to bring their true HDMI 2.0 capable product on the market. The product that I’m looking at today is the Club 3D Mini DisplayPort 1.2 to HDMI 2.0 adapter (CAC-1170). There’s also a full size DisplayPort version.
The spec sheet looks pretty comprehensive.
- Compliant to DisplayPort Specification 1.2 for 1.62Gbps, 2.7Gbps and 5.4Gbps per lane. Effective (video) bandwidth 17.28Gbps
- Compliant to HDMI™ Specification 2.0, data rate up to 6Gbps per TMDS channel. Total throughput 18Gbps
- Supports full link training and no link training
- Repeater for HDCP 1.3 and HDCP 2.2
- 24-bit color and 4:4:4 color sampling
- Internal YCbCr 4:4:4 / 4:2:2 to YCbCr 4:2:0 conversion capability
- Supports UHD resolutions up to 3840 x 2160p @ 60Hz and 1080p 3D
Note! Supports Intel HD Graphics 5000 and newer. I tried it with my Haswell i3 NUC that has HD Graphics 4400 and while it worked, the maximum resolution of 3840×2160 was limited to a refresh rate of 30 frames per second (which I could get with standard HDMI 1.4 without the adapter as well).
Unboxing and Installation
The device is shipped in a relatively big packaging made of recycled paper. Inside you’ll find the adapter itself. The adapter is not very exciting, it’s just a piece of cable with a HDMI 2.0 connector at the other end and Mini DisplayPort connector at the other end. Well, it’s an adapter, what did I expect!? Anyhow, it’s small enough to completely disappear behind your NUC and/or TV.
I plugged it into my Intel NUC6i3SYH (also known as Skylake i3 NUC) that should support 4k @ 60 fps. Then I connected a regular HDMI cable (no need for fancy HDMI 2.0 compatible cables, most of them work) between my Samsung UE48JU6075XXE 4k TV (basically UE48JU6000 series TV) and the adapter. That’s it.
Start the NUC, picture comes up as expected and Windows starts ok. Looks good, but the frame rate initially was only 30 fps. However, the driver let me change to 60 fps and that worked just fine.
I took a short video of using the adapter in both Windows and Linux (OpenELEC).
Of modelines, xorg.conf and xrandr..
When I started my Linux-based HTPC for the first, I was disappointed to see 4k resolution only available with 30 Hz refresh rate. However, after some digging I found out that the TV does not report the 3840×2160 resolution with 60 Hz refresh rate in the EDID data to the NUC. There’s a command xrandr that will print out each supported mode. There was no 3840×2160 with 60 Hz refresh rate.
I found out that this is pretty common and that you can add a mode into the list of supported modes. In my case, the two following commands did the trick.
xrandr --newmode "3840x2160_60" 594.000 3840 4016 4104 4400 2160 2168 2178 2250 +hsync +vsync xrandr --addmode DP1 "3840x2160_60"
Then it was possible to change the mode with the following command.
xrandr --output DP1 --mode 3840x2160_60
Now I’m not sure if it is the adapter or the TV that is not reporting the correct mode back to the NUC. I assume it’s the TV, but am not fully sure. Anyone out there with the same adapter and can get 4k@60fps in Linux without any tricks?
Well, it seems to work. I’ve been happily using the Skylake NUC with my 4k television for a few days. I can get 4k@60 fps out from my i3 Skylake NUC both in Windows and Linux, which is why you want to buy an adapter like this. The price is pretty reasonable as well ($30 / €40 as of Feb 2016) and I expect it to come down as more vendors enter the market. I did not have a chance to try out the HDCP 2.2 support that is claimed for the device, but maybe later then.
This device helps to overcome the other major issue that the HTPC folks had with the Skylake NUC: lack of HDMI 2.0 connectivity. Other than that it’s pretty hard to get too excited about it. It’s just an adapter that seems to do its job.
PS. If you have one with an older firmware, contact Club 3D to upgrade the firmware. Otherwise you might have issues getting your NUC to feed 60 fps modes to your TV.