Lumia 1320 jerky scrolling

[a5cent]

Well I've read it's a known issue with this device. And I only have 2 apps running in the background it's got nothing to do with it anyway. I read it happens on a few apps and sure it does. Do you use Instagram Beta or Games app?? That's where the worst of the jerking is

It is notable that the Lumia 1320 is the WP device with the worst GPU performance / display resolution ratio (out of all WP devices).

This issue also appears to have some relationship to apps that scroll images. The fact that reducing the resolution of downloaded images in the WP Central app alleviates the problem, suggests that this app (and possibly the others as well) might be screwing something up when it comes to down sampling images to a more appropriate resolution for the Lumia 1320.

The default down sampling behaviour has changed between WP8.0 and the WP8.1 developer preview. Which of those are you using on your Lumia 1320?

If you are using WP8.0, it is quite possible that the issue will disappear after upgrading to WP8.1 (no promise though). If that's the case I'd wait for the upgrade, or join the developer preview program. Otherwise let me know.

 

[anon5658834]

It had the same issue on WP8 and 8.1 It doesn't make sense if a Lumia 520 doesn't have such issues but the 1320 with better CPU and more ram does.

 

[a5cent]

It had the same issue on WP8 and 8.1 �� It doesn't make sense if a Lumia 520 doesn't have such issues but the 1320 with better CPU and more ram does.

It does make sense. Both RAM capacity and CPU are almost irrelevant when it comes to UI scrolling performance (Well, RAM capacity actually is entirely irrelevant). That task is handled entirely by the GPU. The GPU in the 1320 is no stronger then the GPU in the Lumia 520, but it must push more than twice as many pixels. That is a huge difference!

In that case I would write an e-mail to all three developers and ask them to test their app on a Lumia 1320. Be sure to mention that based on perceivable performance, they likely aren't scaling their images to an appropriate size for the Lumia 1320.

 

[anon5658834]

It does make sense. Both RAM capacity and CPU are almost irrelevant when it comes to UI scrolling performance (Well, RAM capacity actually is entirely irrelevant). That task is handled entirely by the GPU. The GPU in the 1320 is no stronger then the GPU in the Lumia 520, but it must push more than twice as many pixels. That is a huge difference!

In that case I would write an e-mail to all three developers and ask them to test their app on a Lumia 1320. Be sure to mention that based on perceivable performance, they likely aren't scaling their images to an appropriate size for the Lumia 1320.

Then how do you explain the extreme jerking in the X Box Games menu?? Not even playing a game the menus are horribly laggy

 

[anon5658834]

And also the jerky portrait to landscape movement when in gallery??

 

[salmanahmad]

I believe I know what you mean by jerky scrolling but to be sure please record a video of this issue and upload it to YouTube.
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[mjrtoo]

I thought he already explained it very well. Pixels vs gpu.

 

[anon5658834]

The older Lumia 920 has worse gpu with same screen resolution

 

[salmanahmad]

The older Lumia 920 has worse gpu with same screen resolution

Lumia 920 has an older GPU but a more powerful one I believe. The Adreno 220/225 were high end GPUs of 2012, Adreno 305 is a low end/mid-range GPU of 2013 and 14.

The main difference is that Adreno 300 and above have support for OpenGLES 3.0, compared to the previous OpenGLES 2.0

Most apps as yet aren't optimized for OpenGLes 3.0, so in a world dominated by OpenGLES 2.0 apps naturally the GPU on the 920 should perform much better.

But I am not even sure if Microsoft uses OpenGL or some form of DirectX in Windows Phone.

However the difference between Adreno 225 and 305 are only apparent in gaming.

Maybe app developers haven't gotten around to optimizing their apps for 1320, contact the respective developers of the apps your facing trouble in.

And for god sakes make a video of it. I want to help but I can't fully understand without video.

 

[anon5658834]

Ok cool.

 

[pankaj981]

The jerky scrolling happens on a 1520 on the wpcentral app so its really to the app devs to fix it

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[salmanahmad]

The jerky scrolling happens on a 1520 on the wpcentral app so its really to the app devs to fix it



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Sometimes when I switch from one app to another and then back to WPCentral there is a scrolling delay but after restarting the app it's fine.

 

[anon5658834]

Uploading video now

 

[salmanahmad]

I am not an app developer(yet) but I wonder if apps mistske your Lumia 1320 for a 1520.

If this is true the apps might be thinking your device is a quad core and thus having performance issues.

Maybe this is true, maybe.
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[anon5658834]

Hmm interesting theory

https://www.youtube.com/watch?v=LQhLtTm6GkU

​Here is the video i did my best

 

[salmanahmad]

Hmm interesting theory

https://www.youtube.com/watch?v=LQhLtTm6GkU

​Here is the video i did my best

I am off to sleep, I will check the video in the morning.

 

[a5cent]

Then how do you explain the extreme jerking in the X Box Games menu?? Not even playing a game the menus are horribly laggy

And also the jerky portrait to landscape movement when in gallery??

Hey Sean

I know I'm just one voice on the internet, and you are absolutely justified in being sceptical, but seriously, I'm not BS'ing you. :wink:

The 920 has a far better GPU than the 1320, despite the GPU model number being smaller (Adreno 225 vs. 305). Please note that the model numbers for mobile GPUs have absolutely no relationship to performance.

Anyway, salmanahmad explained that part very well, but you don't have to take his or my word for it. A benchmarking website can provide certainty.

Anyway, it all boils down to what I said in my first post:

Out of all WP devices, the 1320 has the worst GPU performance / display resolution ratio.

Now that I've seen the video, I'd say that sentence likely explains all the issues you are seeing. It's impossible to be 100% sure without having access to the source code, but I think it's a very safe bet. You have no hope of improving anything here yourself. If anything can be improved, that is entirely in the hands of app developers. All you can do is ask developers to test their apps using a Lumia 1320 and see if they can do anything to reduce stutter/lag.

I'd wager that any app scrolling through a list of large images will exhibit similar symptoms.

I'm not exactly sure how an app would confuse itself into thinking it's running on a Lumia 1520 while actually running on a 1320. However, I could imagine an app determining that it is running on a device with a 720p display and then falsely assuming it has a Lumia 920 class GPU to power graphics operations. Like I said... the 1320 is the only device that pairs a 720p display with a Lumia 520 class GPU.

 

[anon5658834]

Ok I understand all that now. But why would Microsoft's own X Box Games app be so laggy?? Not playing a game but just the menus??

 

[salmanahmad]

Despite Adreno 305 not being a high end GPU it does power a lot of 720p displays pretty smoothly.

Take for example Galaxy Grand 2 or HTC Desire 816, these phones are run by Adreno 305 at 720p resolution.

I see two possible explanations:

1. Maybe the device is a defected model(very unlikely)

2. Apps haven't been properly optimized for Lumia 1320(likely)
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[salmanahmad]

Honestly from your video I can't see if there really is any scrolling problems, it seems pretty smooth from the video at least. There was just that one small hiccup when you were scrolling in Instagram.

Here is another scrolling issue on Windows Phone but this one only occurs on devices using the Adreno 305 GPU(and possibly older Adreno 225 GPUs)

https://www.youtube.com/watch?v=n9pdzH0UpXY