Why are refresh rates "off" by a bit?

Everything about displays and monitors. 120Hz, 144Hz, 240Hz, 4K, 1440p, input lag, display shopping, monitor purchase decisions, compare, versus, debate, and more. Questions? Just ask!
User avatar
LagBuster
Posts: 71
Joined: 15 May 2014, 06:50

Re: Why are refresh rates "off" by a bit?

Post by LagBuster » 09 Dec 2019, 14:38

DWM performance at 62.9 Hz is consistent, but I get repeated frames during video playback. If I go back to 60 Hz DWM is stuttery but I don't get repeated frames... :evil:

EDIT: Although, now I'm thinking that maybe those repeated frames don't matter. At 62 Hz I get exactly 2 repeated frames every second (60 fps video with madVR), which makes sense. I suppose it only matters statistically speaking, then?
Last edited by LagBuster on 09 Dec 2019, 15:31, edited 1 time in total.

User avatar
RealNC
Site Admin
Posts: 3023
Joined: 24 Dec 2013, 18:32
Contact:

Re: Why are refresh rates "off" by a bit?

Post by RealNC » 09 Dec 2019, 19:05

Well, 30FPS video needs 60Hz. Obviously. 24FPS video needs 48Hz or 72Hz (or 96Hz, or 120Hz, etc).

(This is why 120Hz is such a good desktop refresh rate and preferred even if your monitor can do 144Hz. 120Hz matches 24FPS, 30FPS and 60FPS video, which are the most used video frame rates.)
SteamGitHubStack OverflowTwitter
The views and opinions expressed in my posts are my own and do not necessarily reflect the official policy or position of Blur Busters.

User avatar
LagBuster
Posts: 71
Joined: 15 May 2014, 06:50

Re: Why are refresh rates "off" by a bit?

Post by LagBuster » 09 Dec 2019, 19:17

RealNC wrote:
09 Dec 2019, 19:05
Well, 30FPS video needs 60Hz. Obviously. 24FPS video needs 48Hz or 72Hz (or 96Hz, or 120Hz, etc).

(This is why 120Hz is such a good desktop refresh rate and preferred even if your monitor can do 144Hz. 120Hz matches 24FPS, 30FPS and 60FPS video, which are the most used video frame rates.)
Yeah, I guess so. I'm only using 60 Hz because of 4K. With madVR I can tell it to change to any refresh rate when the playback starts, but it's not ideal.

User avatar
Chief Blur Buster
Site Admin
Posts: 7857
Joined: 05 Dec 2013, 15:44
Location: Toronto, Ontario, Canada
Contact:

Re: Why are refresh rates "off" by a bit?

Post by Chief Blur Buster » 09 Dec 2019, 19:54

LagBuster, do you have VRR turned on or off?

A compositor with VRR enabled, sometimes has occasionally erratic dips in refresh framepacing. Not always, but it does sometimes deviate from the max-Hz framerate.
Head of Blur Busters - BlurBusters.com | TestUFO.com | Follow @BlurBusters on Twitter

       To support Blur Busters:
       • Official List of Best Gaming Monitors
       • List of G-SYNC Monitors
       • List of FreeSync Monitors
       • List of Ultrawide Monitors

User avatar
LagBuster
Posts: 71
Joined: 15 May 2014, 06:50

Re: Why are refresh rates "off" by a bit?

Post by LagBuster » 09 Dec 2019, 20:00

Chief Blur Buster wrote:
09 Dec 2019, 19:54
LagBuster, do you have VRR turned on or off?

A compositor with VRR enabled, sometimes has occasionally erratic dips in refresh framepacing. Not always, but it does sometimes deviate from the max-Hz framerate.
It's off, Chief.

Right now I'm testing 60.003 CRU Hz, which gives me the closest frequency to real 60 Hz, and I haven't noticed any stutters while web browsing yet. But with the YouTube 4K 60 fps video it's the same story.

User avatar
LagBuster
Posts: 71
Joined: 15 May 2014, 06:50

Re: Why are refresh rates "off" by a bit?

Post by LagBuster » 09 Dec 2019, 20:59

I will try to do a proper frame time analysis tomorrow or in a couple of days, and then I'll have more information.

EDIT: I went ahead and did a couple quick ones just now. This is what I'm talking about:

Default 59.981 CRU Hz

Image

OC 62.9 CRU Hz

Image

Sorry for double posting, didn't realize that I can only delete my latest post.

User avatar
Chief Blur Buster
Site Admin
Posts: 7857
Joined: 05 Dec 2013, 15:44
Location: Toronto, Ontario, Canada
Contact:

Re: Why are refresh rates "off" by a bit?

Post by Chief Blur Buster » 09 Dec 2019, 21:27

That's quite weird that framepacing is better at 62.9 Hz than at 59.981 Hz.

There must be something abnormal going on. Are you sure this is a single-monitor setup? The only time I saw this happen was when using a multi-monitor setup, where the Hz is at least slightly different between monitors. Windows has a really bad time synchronizing when multiple things are going on simultaneously on different monitors. For that situation, I temporarly disable all secondaries and only prioritize the main monitor.

Also, verify for power management quirks. There might be some erratic enabling/disabling of power management if your video uses less than 5%-10% of GPU, it sometimes interferes with framepacing of video playback because when so little GPU power is used, it starts power-management, which then starts interfering with framepacing sometimes -- a recurring problem that plagues TestUFO sometimes. Try changing power plan to High Performance and seeing what happens.
Head of Blur Busters - BlurBusters.com | TestUFO.com | Follow @BlurBusters on Twitter

       To support Blur Busters:
       • Official List of Best Gaming Monitors
       • List of G-SYNC Monitors
       • List of FreeSync Monitors
       • List of Ultrawide Monitors

User avatar
LagBuster
Posts: 71
Joined: 15 May 2014, 06:50

Re: Why are refresh rates "off" by a bit?

Post by LagBuster » 10 Dec 2019, 07:36

Chief Blur Buster wrote:
09 Dec 2019, 21:27
That's quite weird that framepacing is better at 62.9 Hz than at 59.981 Hz.

There must be something abnormal going on. Are you sure this is a single-monitor setup? The only time I saw this happen was when using a multi-monitor setup, where the Hz is at least slightly different between monitors. Windows has a really bad time synchronizing when multiple things are going on simultaneously on different monitors. For that situation, I temporarly disable all secondaries and only prioritize the main monitor.

Also, verify for power management quirks. There might be some erratic enabling/disabling of power management if your video uses less than 5%-10% of GPU, it sometimes interferes with framepacing of video playback because when so little GPU power is used, it starts power-management, which then starts interfering with framepacing sometimes -- a recurring problem that plagues TestUFO sometimes. Try changing power plan to High Performance and seeing what happens.
Chief, I only have one monitor and one DP cable plugged in, but I noticed something strange going on. It seems that sometimes Windows doesn't recognize my monitor properly, and that results in CRU saying there's no active profile, which is weird because I can change to the custom refresh rate that I set using CRU, so that custom profile must be active somehow. I took some screen captures so that you can see what I mean.

Image

Image

Image


If I run CRU's restart64.exe this behavior gets fixed.

Image

Image

Image


Regarding power saving modes, I'm seeing that Windows power plan only affects CPU clocks, not GPU clocks, but High Performance vs. Balanced made no difference. There doesn't seem to be any way of forcibly disabling GPU power saving states (not for my old GPU, anyway).

User avatar
LagBuster
Posts: 71
Joined: 15 May 2014, 06:50

Re: Why are refresh rates "off" by a bit?

Post by LagBuster » 10 Dec 2019, 10:10

To make matters even worse, I also experience this issue where performance gets "locked" to 20 fps and I have no idea what triggers it. To fix it I open a Windows Explorer window and move it around a bit and that unlocks the frame rate. :lol:

Image

Image

User avatar
RealNC
Site Admin
Posts: 3023
Joined: 24 Dec 2013, 18:32
Contact:

Re: Why are refresh rates "off" by a bit?

Post by RealNC » 10 Dec 2019, 11:08

Never seen anything like this. Only thing I can think of is that something you installed in your machine messes things up. Some driver, some utility, something...
SteamGitHubStack OverflowTwitter
The views and opinions expressed in my posts are my own and do not necessarily reflect the official policy or position of Blur Busters.

Post Reply