Core i7-5775C won't display 4K@60Hz

[MAlla4]

I just upgraded my CPU from a i7-4790 (non-K) to an i7-5775C on an ASUS Z97-WS motherboard.

The Z97-WS has been connected to an Acer B286HK 4K/60Hz monitor for a year.

The Haswell i7-4790 had no problem displaying 4K/60Hz/DP1.2 on its DP and miniDP ports.

The 5775C is now defaulting to 4K/30Hz on both DP ports despite the monitor being in DP 1.2 mode (unchanged).

I'm running driver 20.19.15.4463. I also tried the previous .4444 driver with the same result.

Situation:

• The same cable and monitor worked with the Haswell 4790 CPU, Quadro K620, GTX 980 at 4K/60Hz.
• The same cable and monitor worked with the somewhat similar NUC 5i5RYH / HD6000 at 4K/60Hz.
• I see that my workstation reports a video BIOS of 1029 while the NUC 5i5RYH has a video BIOS of 1039.
• Additionally, the workstation used to be able to display the UEFI BIOS interface on the 4K monitor but the 5775C doesn't display anything until Win10/x64 fully boots.
• Platform: Win10/x64 + Acer B286HK 4K/60Hz + Core i7-5775C

So... what's the problem? Is the motherboard BIOS's Intel Video BIOS too old and I need ASUS to upgrade it?

I really need this fixed as it's my daily workstation.

The EDID dump of the Acer B286HK is here:

[idata]

Please copy-paste or attach the Graphics report generated within the Intel(R) Graphics User Interface. To access this report, see the following URL:

http://www.intel.com/content/www/us/en/support/graphics-drivers/000005848.html?wapkw=graphics+report http://www.intel.com/content/www/us/en/support/graphics-drivers/000005848.html?wapkw=graphics+reportAllan.

[MAlla4]

Report attached.

[idata]

This seems to be an issue with monitor EDID or monitor drivers.

I have checked Acer's website but I do not see monitor INF drivers for Windows® 10, I see Windows® 7 and 8.http://global-download.acer.com/GDFiles/Driver/Monitor/Monitor_Acer_1.0_W8x64W8x86W7x64W7x86_A.zip?acerid=635393435454840588&Step1=MONITOR&Step2=B%20SERIES&Step3=B286HK&OS=ALL&LC=en&BC=ACER&SC=PA_6 http://global-download.acer.com/GDFiles/Driver/Monitor/Monitor_Acer_1.0_W8x64W8x86W7x64W7x86_A.zip?acerid=635393435454840588&Step1=MONITOR&Step2=B%20SERIES&Step3=B286HK&OS=ALL&LC=en&BC=ACER&SC=PA_6You could try to install then with compatibility mode. Allan.

[MAlla4]

That doesn't sound right to me.

The same workstation is being used and the 4790 Haswell was swapped with a 5775C Broadwell CPU.

Same cable, same monitor, same Win10/x64.

[MAlla4]

I successfully updated the monitor driver by booting Win10 with the allow unsigned driver startup option.

It didn't help and the 4K monitor is still running at 30Hz.

The HD Graphics driver is correctly reading the EDID whether the Generic or Win8 monitor driver is installed (see last image).

So... the question remains unanswered. Why is a 5775C not driving 4K/60Hz over its DP ports while an older 4790 works perfectly?

[MAlla4]

Is it possible the BIOS of my motherboard is the culprit?

The VBIOS and GOP drivers in the BIOS are quite old and according to Intel documentation there were a number of fixes for Broadwell in the interim.

The latest VBIOS is around 1039 and the latest GOP driver is 1033.

Can Intel engineers confirm if this is something that could result in a Broadwell C processor not showing the BIOS setting screen on the monitor and not running on Windows 10/x64 at 4K/60Hz?

Intel OROM VBIOS and EFI GOP Driver

OROM VBIOS HSW-BDW - 1029

EFI GOP Driver HSW-BDW - 5.5.1024

EFI GOP Driver HSW-BDW - 5.5.1024

[idata]

I am currently researching on this issue. As soon as I can, I will send you a message with my findings. Thank you for your patience and understanding.

Allan.

[MAlla4]

Thanks.

I've also attached a more detailed EDID/MonInfo dump for the Acer B286HK.

[idata]

Thank you for the attachment, I will also need the following information to be filled out completely:

http://https://communities.intel.com/thread/77761 http://https://communities.intel.com/thread/77761Allan.

[MAlla4]

Category

Questions

Answers (N/A if not applicable)

Description

Provide a detailed description of the issue

A system upgraded with a Core i7-5775C CPU no longer drives a 4K monitor at 60Hz.

Instead, the Broadwell i7-5775C drives the monitor at 4K/30Hz.

Previous CPU was an i7-4790 and drove 4K/60Hz on both IGP DP ports.

Please place an X to the right of the option showing how often you see this issue using specific steps. (Ex: 'Every few times a game is started it flickers.' <- This would be "Often")<p> 

Always

Hardware (HW)

Brand and Model of the system.

ASUS Z97-WS / BIOS 2403

Hybrid or switchable graphics system?

ie Does it have AMD or NV graphics too?

Integrated graphics being used for display. Two NV cards in PCIe 3.0 slots.

Make and model of any Displays that are...

[idata]

Thank you for the files and the report.I will update this thread as soon as I receive more details about this issue.

Allan.

[MAlla4]

Any progress on this issue?

Still living at 30Hz.

[idata]

I was able to get 3840x2160p@60hz via DisplayPort. Even though in my test I was using Intel® Iris 540, the driver version is the same 20.19.15.4463 as the one for Iris Pro Graphics 6200.

If this was a driver issue, I would expect having same situation, the problem might be external.

See attachments:

Allan.

[MAlla4]

That's helpful that you were able to test on a B286HK.

Now you understand my issue.

The same motherboard + cable + monitor runs at 3840x2160@60Hz with a Core i7-4790.

The same motherboard + cable + monitor but with a Core i7-5775C runs at 30Hz and doesn't even offer 60p Hz as a choice.

[Allan_J_Intel1]

Please test driver version 4474:

https://downloadcenter.intel.com/download/26099/Intel-Beta-Graphics-Driver-for-Windows-10-and-Windows-7-8-1-15-40-?product=89174 Download Intel® Beta Graphics Driver for Windows® 10 and Windows 7*/8.1* [15.40]

Allan.

[MAlla4]

4474 Beta doesn't help.

I also have a newer BIOS from ASUS.

Still stuck at 30Hz while i7-4790 and various discrete NVIDIA cards work fine with same cable/monitor:

[MAlla4]

With help from ASUS and a new BIOS revision the 5775C now drives the Acer monitor at 4K/60Hz.

Problem solved!

[idata]

I am glad to hear this is working for you.

Thank you for sharing this information. Allan.