P2715Q @ 30 Hz would like @ 60 Hz

Question

HenkDawson Author

Level 1

13 points

P2715Q @ 30 Hz would like @ 60 Hz

I would like to set my DELL P2715Q display to @ 60 Hz but it is stuck @ 30 Hz

Any ideas?

Display: Del P2715Q

MST: greyed out - no option to change

Response time: set to Normal

Refresh rate: 30fps

(See details below)

Computer: 2019 Mac Pro

macOS: Catalina Version 10.15.2

Graphics Card: AMD Radeon Pro Vega II

DELL P2715Q Details:

Resolution: 5120 x 2880 (5K/UHD+ - Ultra High Definition Plus)

UI Looks like: 2560 x 1440 @ 30 Hz

Framebuffer Depth: 30-Bit Color (ARGB2101010)

Display Serial Number: X24K16BJ154L

Main Display: Yes

Mirror: Off

Online: Yes

Rotation: Supported

Automatically Adjust Brightness: No

Connection Type: DVI or HDMI

Adapter Firmware Version: 7.55

Mac Pro

Posted on Dec 31, 2019 12:55 PM

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Answer 1

MrHoffman

Level 10

158,529 points

Dec 31, 2019 1:13 PM in response to HenkDawson

Switch from HDMI to DP?

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Answer 2

Dec 31, 2019 1:47 PM in response to HenkDawson

DVI and HDMI are called "Legacy" interfaces. They still contain the "heartbeat" refresh required to run a CRT display. That means that every refresh cycle (60 times a second) you use up bandwidth and generate heat sending the exact same stuff as the last frame -- even if it did not change. And using TrueTone, you have no time for additional data or faster refresh rates.

DisplayPort family (which is also what is inside Thunderbolt-direct) requires a display with a display buffer. But it drops the "heartbeat" refresh and only sends the changes. When the screen stops changing, the link goes nearly quiet. It can easily achieve higher average refresh rates, does not flicker because the actual refresh comes from the display itself, and runs much cooler because there are far fewer bits being fetched, rasterized, and sent.

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