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RX 5700 XT - 75 Hz/144 Hz/non-standard refresh rates causing VRAM clock to run at max

Cheeseball

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Hey guys,

If you're in the same situation as I am with my RX 5700 XT where the memory clock is running at maximum speed at 144 Hz even though you're idle (desktop, non-3D software, etc.), it looks like u/BrainMuncher was able to deduct why this happens and a possible fix:


I will be trying this out with my Dell monitor after work. I've been running at 120 Hz with the monitor not overclocked. Hopefully changing the pixel clock would allow me to hit 144 Hz (or near 144 Hz) and make use of the monitor as it was designed.
 
do let us know your results please

I will. I will try as much as I can within the Adrenalin (I'm currently running 19.10.2 Optional) Custom Resolutions sections first and if no change, will switch to CRU. Screenshots of my journey will be posted as well.
 
FYI, if you have more than one monitor connected to a GCN/RDNA card, the VRAM will always run at maximum clock and it will never deviate from it.
 
I am running my 5700XT with a PG279Q at 144hz with no problem, the vram stays at 100mhz when in idle
Didn't try with newer drivers... i am still with 19.9.1
 
FYI, if you have more than one monitor connected to a GCN/RDNA card, the VRAM will always run at maximum clock and it will never deviate from it.

This is unfortunately true. I have tried this with my mentioned Dell monitor (through DisplayPort) and another BenQ 1080p monitor through HDMI. This was a 120 Hz and 60 Hz, and turning off the BenQ would drop the clocks.

I am running my 5700XT with a PG279Q at 144hz with no problem, the vram stays at 100mhz when in idle
Didn't try with newer drivers... i am still with 19.9.1

This happens on certain monitors as AMD had to implement a workaround to avoid screen flickering on monitors that do not use the standard VBLANK timings. ASUS got the timing right with your PG279Q, and I would hope so because that thing is $500+.
 
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Hmm, all my gpus ran with 3D vram clocks at 144hz. Is this a different thing?
 
This is pretty common with multi screen setups. Less common with high refresh on the desktop, but can still happen.

Hmm, all my gpus ran with 3D vram clocks at 144hz. Is this a different thing?

No. It depends on the GPU in idle clocks and the performance required to drive the panel. If there is a mismatch or slight risk of one, the clocks will go up. The detection of this is / has been hit-miss though. Smaller GPUs are more likely to get into trouble, after all a big one has way more resources at idle clock.
 
Apparently putting my Pixel clock to 340 MHz works with my Dell S2419HGF. Please take note that this contains one of those panels that needs to have "Overclocked" turned on in the monitor settings to achieve 144 Hz, otherwise it will just run at a max of 120 Hz if it's turned off. I have Response Time on Normal as any other settings causing ghosting.

FreeSync is still enabled.

@W1zzard - Please let me know if you need more information.

itworks_S2419HGF.PNG
itworks2_S2419HGF.PNG


Take note that this is not the full 144 Hz, but 141 Hz, as reducing Pixel clock to an exact 340.00 will align the Refresh rate at 141.280 Hz.

141_ahwell.PNG
 
Hey Cheeseball I thought I should mention (if only for posterity if people come here from google) that for my monitor I didn't add a new resolution, but edited the existing one. The 144Hz mode was in the extension block. I have no idea why it is set up like this, or if it even matters. But there you have it.

136136
 
FYI, if you have more than one monitor connected to a GCN/RDNA card, the VRAM will always run at maximum clock and it will never deviate from it.
This is unfortunately true. I have tried this with my mentioned Dell monitor (through DisplayPort) and another BenQ 1080p monitor through HDMI. This was a 120 Hz and 60 Hz, and turning off the BenQ would drop the clocks.



This happens on certain monitors as AMD had to implement a workaround to avoid screen flickering on monitors that do not use the standard VBLANK timings. ASUS got the timing right with your PG279Q, and I would hope so because that thing is $500+.

Seeing as idle memory clocks are still an issue I see no reason not to keep this thread alive (unless there's a new thread I haven't found)

Did some testing at idle with different display configurations with a 5700 XT and two displays
Monitor 1: 1440p/144hz samsung display connected with DP
Monitor 2: 1080p/60hz TV connected with HDMI.

Locked means stuck at 875MHz and unlocked is variable, down to 100MHz.

1440p/144hz monitor 1 only: unlocked
1080p/60hz monitor 2: unlocked

Running monitor 2 @ 1080p/60 together with monitor 1 at settings below gave following results:
1440p/60hz: locked
1440p/30hz: unlocked
1080p/144hz: locked
1080p/60hz: unlocked

So with up to 1440p/30hz or 1080p/60hz on 1st display and 1080p/60hz on 2nd display with extended desktop the memory clock speed is in fact not locked at 875 MHz but moves between the 4 frequency steps, despite what previous posts indicate.
It doesn't seem like locked vram frequency is strictly depending on number of monitors (1 or more) or res/hz of a single monitor but a combination of the 2.

Is the "issue" then that the amount of memory bandwidth needed for certain setups, even at idle, requires memory to stay at max clocks? There seems to be somewhat of a threshold issue here since the jump in needed bandwidth then isn't linear with the resolution, which sounds to me like something AMD could easily tweak in the drivers...
 
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Is the "issue" then that the amount of memory bandwidth needed for certain setups, even at idle, requires memory to stay at max clocks? There seems to be somewhat of a threshold issue here since the jump in needed bandwidth then isn't linear with the resolution, which sounds to me like something AMD could easily tweak in the drivers...

Without knowledge of how the GPU works internally, there's not much point in speculating on what the actual problem could be IMO (although it's always fun to speculate!). But the fact that single-monitor is always fine, while multi-monitor is sometimes not, makes it almost certain that there's a different logic path (through the drivers, or the RAMDAC, or even the physical hardware) taken when multiple outputs are present, and that there's a bug somewhere on that path that isn't present on the single-monitor path. AMD simply needs to find and fix that bug.
 
OT, but AFAIK due to Windows' feature, for multi monitor, the refresh rate should be 1:1, 1:2 etc.. so your 2nd monitor should be 72Hz when running 144Hz on the main screen.

Correct me if I'm wrong.
 
Without knowledge of how the GPU works internally, there's not much point in speculating on what the actual problem could be IMO (although it's always fun to speculate!). But the fact that single-monitor is always fine, while multi-monitor is sometimes not, makes it almost certain that there's a different logic path (through the drivers, or the RAMDAC, or even the physical hardware) taken when multiple outputs are present, and that there's a bug somewhere on that path that isn't present on the single-monitor path. AMD simply needs to find and fix that bug.
This is no bug, same was Nvidia. If you need multimonitor/custom resolution, you need to learn CRU.
Same as before
 
Seeing as idle memory clocks are still an issue I see no reason not to keep this thread alive (unless there's a new thread I haven't found)

Did some testing at idle with different display configurations with a 5700 XT and two displays
Monitor 1: 1440p/144hz samsung display connected with DP
Monitor 2: 1080p/60hz TV connected with HDMI.

Locked means stuck at 875MHz and unlocked is variable, down to 100MHz.

1440p/144hz monitor 1 only: unlocked
1080p/60hz monitor 2: unlocked

Running monitor 2 @ 1080p/60 together with monitor 1 at settings below gave following results:
1440p/60hz: locked
1440p/30hz: unlocked
1080p/144hz: locked
1080p/60hz: unlocked

So with up to 1440p/30hz or 1080p/60hz on 1st display and 1080p/60hz on 2nd display with extended desktop the memory clock speed is in fact not locked at 875 MHz but moves between the 4 frequency steps, despite what previous posts indicate.
It doesn't seem like locked vram frequency is strictly depending on number of monitors (1 or more) or res/hz of a single monitor but a combination of the 2.

Is the "issue" then that the amount of memory bandwidth needed for certain setups, even at idle, requires memory to stay at max clocks? There seems to be somewhat of a threshold issue here since the jump in needed bandwidth then isn't linear with the resolution, which sounds to me like something AMD could easily tweak in the drivers...
RDNA is apparently capable of dropping the mem clocks where GCN couldn't. So I was wrong about that above.

Even if not doing anything, the memory still has to be available to send current frames to the monitor. Assuming your displays are 24-bit, Monitor 1 requires ‭1,592,524,800‬ bytes/second and Monitor 2 requires ‭373,248,000‬ bytes/second. Stock 5700/XT is 448 GB/s. You'd think at 100 MHz, it has more than enough bandwidth to keep the monitors updated but...that's not how it is set up.

If a card does not natively support analog out (Navi doesn't), there is no RAMDAC.

OT, but AFAIK due to Windows' feature, for multi monitor, the refresh rate should be 1:1, 1:2 etc.. so your 2nd monitor should be 72Hz when running 144Hz on the main screen.

Correct me if I'm wrong.
My card is idle right now and memory bounces between 200-700 MHz. Both of my monitors are 60 Hz.
 
...
Did some testing at idle with different display configurations with a 5700 XT and two displays
Monitor 1: 1440p/144hz samsung display connected with DP
Monitor 2: 1080p/60hz TV connected with HDMI.

Locked means stuck at 875MHz and unlocked is variable, down to 100MHz.

1440p/144hz monitor 1 only: unlocked
1080p/60hz monitor 2: unlocked

Running monitor 2 @ 1080p/60 together with monitor 1 at settings below gave following results:
1440p/60hz: locked
1440p/30hz: unlocked
1080p/144hz: locked
1080p/60hz: unlocked
...

If possible, could you try these three combinations and let us know if they're "locked" (stuck at 875MHz memory):

Monitor 1: 1080p/144 Hz
Monitor 2: 1080p/72 Hz

Monitor 1: 1080p/120 Hz
Monitor 2: 1080p/60 Hz

Monitor 1: 1440p/120Hz
Monitor 2: 1080/60 Hz


My card is idle right now and memory bounces between 200-700 MHz. Both of my monitors are 60 Hz.

It is free to clock up when needed (like if you open up a video or software that displays 3D objects, like Wallpaper Engine), but it should generally idle at 100 MHz.
 
This is no bug, same was Nvidia. If you need multimonitor/custom resolution, you need to learn CRU.
Same as before

That forum post is 9 years old. In other words, NVIDIA has managed to not have this problem for nearly a decade. AMD, in contrast, has done nothing to fix it in that same amount of time. So, good job on proving my point!
 
If possible, could you try these three combinations and let us know if they're "locked" (stuck at 875MHz memory):

Monitor 1: 1080p/144 Hz
Monitor 2: 1080p/72 Hz

Monitor 1: 1080p/120 Hz
Monitor 2: 1080p/60 Hz

Monitor 1: 1440p/120Hz
Monitor 2: 1080/60 Hz


My card memory is stuck no matter what. 1440p at any refresh rate tried 144,120,60hz even cru. Hdmi or DP. Single monitor or multiple monitors. I have been told it is expected behavior @144hz by AMD support. However they are unable to provide excuses for any other refresh rate...
 
My card memory is stuck no matter what. 1440p at any refresh rate tried 144,120,60hz even cru. Hdmi or DP. Single monitor or multiple monitors. I have been told it is expected behavior @144hz by AMD support. However they are unable to provide excuses for any other refresh rate...

Acer ed323quara? Use the method @BrainMuncher mentioned above. That should work for your monitor.

If you have two of those monitors, you should be good once you're done with the CRU method too since both would be doing 144 Hz.
 
Acer ed323quara? Use the method @BrainMuncher mentioned above. That should work for your monitor.

ED323QUR Abidpx (just noticed typo in specs) but those are 144hz Va panels. Default pixel clocks are around 500. Not sure if is it safe to deviate, so much from default timings.
 
ED323QUR Abidpx (just noticed typo in specs) but those are 144hz Va panels. Default pixel clocks are around 500. Not sure if is it safe to deviate, so much from default timings.

It's fine. Even if it shows 500, it should still work as that is supposedly the native clocks of that panel. Try it out.
 
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