Dell XPS 13 (2015) - is there a 4k@60 fps support for external display.

[Doroga]

Looking to buy a new Dell XPS 13 laptop, but can't find any information on supported framerate for 4K external display.

I tried looking for Broadwell 4K support in general but there is no much info there.

Recent Anandtech Broadwell article only mentioned that U processors now will be able to support 4K@30 FPS via HDMI, but sadly there is nothing said about 4K via DisplayPort.

In most other places just 4K support is mentioned without refresh rate information.

Would be great if anyone knows for sure or will be able to test with live laptop.

 

[thecoolnessrune]

Intel has supported DP1.2 with HBR2 since their HD4200 IGP in both SST and MST modes. This is good for UHD at 60Hz, and 4Kx2K at 50Hz (while DisplayPort 1.2 with HBR2 supports 60Hz for 4Kx2K, the vast majority of graphics cards and all current IGPs are not clocked high enough in the LVDS to transmit higher than 50Hz at that resolution).

Broadwell-U also supports this same displayport standard. Unless Dell has intentionally lowered the clock of the LVDS for power consumption or thermal purposes, there's no reason why the Displayport cannot support the full 1.2 HBR2 standard. Given that the laptop has the option of coming with a UHD panel, I find it unlikely that the LVDS is clocked lower on the external port

Naturally very few, if any have these laptops in-hand yet, so asking for a live laptop test (with a 4K screen no less), is a bit pre-mature. But by deduction, it's extremely unlikely that this laptop would not have the capability.

 

[alcoholbob]

I'll be interested when we start seeing high end Iris Pro IGPs on these CPUs. The Broadwell U that Dell use in the XPS 13 are still 5000 series IGPs...meh. Can't even run Diablo 3 at 1080p.

 

[Doroga]

Thanks, thecoolnessrune.

I still have a few weeks to think about order, so maybe some real owner would pop up to confirm Dell handles UHD as expected.

But still it's great to see mDP on this Dell, seeing only miniHDMI on modern laptops is a pain.

 

[Doroga]

I've finally found Broadwell datasheet:
http://www.intel.com/content/www/us/en/processors/core/5th-gen-core-family-datasheet-vol-1.html

It looks like any non-Y (not a Core M) processors can support UHD@60 Hz for both internal and external monitors, unless specifically configured for reduced Link Data Rate by OEMs. So I'll just have to keep my fingers crossed that Dell did their job ok.

Core M processors only support up to 3200*2000 resolution @60 Hz and additional cooling may be required in that case.

Kind of limited for docked usage with a proper screen unless you plan to upgrade in 1-2 years.

 

[thecoolnessrune]

I'll be interested when we start seeing high end Iris Pro IGPs on these CPUs. The Broadwell U that Dell use in the XPS 13 are still 5000 series IGPs...meh. Can't even run Diablo 3 at 1080p.

HP Sells the Envy 15t touch slim laptop (since AMD systems can't use the Ultrabook term) that features AMD's FX-7500 CPU with an R7 IGP. It's performance is just under the Iris Pro 5200 GPU used DTR notebooks, and is far faster than anything in the Intel Ultrabook camp. The CPU side is about as good as an i3 in single-threaded tasks, and a midrange i5 in multi-tasking workloads. An FX-7500 based CPU and 1080P screen option runs just under $900 (which is good, because you'll want to take the extra money and put a not sucky SSD in it).

At 1080P Ultra Settings, an Iris Pro 5200 gets about 46FPS in Diablo 3, so a FX-7500 should manage around 40FPS. That's pretty respectable for something that doesn't have the benefit of eDRAM and has less than half the TDP (The FX-7500 is a 19W TDP processor, while the Iris Pro 5200 is only available in 55W Desktop Replacement Notebook segments).

If you mean that you're waiting for something with enough performance to run AAA games at 1080P low settings in a 15/19W Ultrabook TDP, then you'll be waiting around for a long time. That's 750Ti/ R7 260 territory, which even if we look at the 750 Ti, is a 60 watt TDP. Even if we keep performance static, and hope the 20nm transition comes within a year, you're talking about a 25% ideal power savings + a little extra for better binning / fewer board components, which means a 30-35 watt GPU still being required. Lets give it the benefit of the doubt, and say that next-gen architectures cut another 10 watts and we get down to 35 Watt. You're still over double the TDP required for an Ultrabook and haven't even included the CPU yet! These numbers bear out in the real world because the NVIDIA GTX 860M is essentially 100% of a 750 Ti and it has a 45 watt TDP.

It's simply going to take a while for us to get down there, but as with most computer progress, it will happen eventually

 

[thecoolnessrune]

I've finally found Broadwell datasheet:
http://www.intel.com/content/www/us/en/processors/core/5th-gen-core-family-datasheet-vol-1.html

It looks like any non-Y (not a Core M) processors can support UHD@60 Hz for both internal and external monitors, unless specifically configured for reduced Link Data Rate by OEMs. So I'll just have to keep my fingers crossed that Dell did their job ok.

Core M processors only support up to 3200*2000 resolution @60 Hz and additional cooling may be required in that case.

Kind of limited for docked usage with a proper screen unless you plan to upgrade in 1-2 years.

Monitor number would also matter Non-Y Broadwells should support 3 monitors (including the built-in monitor). Y Broadwells only support 1.