Laggy performance system wide in Oreo seemingly narrowed down to OCR? Or is it a 4 GB RAM problem?

Phone: Samsung S8 (G950U)
Android version: 8.0
Samsung Experience: 9.0

I've noticed that my phone will have sometimes have severe slowdowns when doing any actions requiring changing from portrait to landscape after phone has been up a while. Full screen in Youtube? 30 seconds of frozen screen, audio only. Camera app? Will just totally freeze for tens of seconds if flipped to landscape. Phone desktop to landscape view? Equally laggy.

I've been experimenting with system settings, and by chance, force stopped Pleco after having used OCR. Suddenly, my phone portrait -> landscape rotations were working as if in safe mode. To eliminate a variable, I did a regular dictionary search in Pleco -- no effect on speed of landscape switches. I ran OCR on some characters and tried rotations, and I could notice a difference immediately. I checked my RAM usage, and it was around 700-900 MB free IIRC.

The core of my post is: Are there any folks with the latest, speediest Android devices who can notice system wide slowdowns after using OCR? Or perhaps more likely, is my 4 GB RAM S8 just starting to get a little long in the tooth, and Pleco is just the straw that broke the camel's back?
Hi ouboss,

that's an interesting phenomenon. On my one-year-old OnePlus 3T, I could still easily switch to landscape in YouTube after using Pleco Live OCR. It only froze for maybe 0.75 seconds as it was changing the screen orientation. Could it be that your Samsung S8 has anti-virus software on it, or something else that works close to the kernel? What if you try factory resetting the phone and reinstalling software one by one, then check when the freezes return?

Hope this helps at least a bit!


Thank you for your input!

On the contrary, I've had my anti-virus disabled recently while searching for the cause of my lag. I'm just settling into a new position ATM, but a factory reset is on the horizon once things settle down here.

I might try a different launcher than the default Samsung one in the meantime, since your OnePlus is working smoothly.


Staff member
Is Pleco's Screen Reader or Clip Monitor function turned on? Can you disable them and see if that helps?

It *could* be something on our end, but you're on a new enough version of Android that it shouldn't really even be possible for our app to aggressively churn away on your CPU when it's in the background unless you're running one of our background services, so if you're not then my best guess would be that it is in fact RAM pressure.
I would typically use Screen OCR for just about any situation. When I encountered a slowdown, a force close of Pleco would bring things back up to speed. I don't think it was Pleco's fault to be clear now, because in my newly factory reset phone, "Developer options>Running services>Show cached processes" will typically hover around 100 MB free, around 400 MB free after a 'clear all recent' action. I've been extra selective this time around, and yet my phone now is no better off than the best of times before, albeit not as bad as the worst of times.

tl;dr: Mike, I concur with you about RAM pressure.
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Staff member
Screen OCR could slow down the phone in the background, in theory; does it speed things up if you turn that off?

On some devices, due to a bug in the implementation of Android's media projection system, even when Screen OCR is turned off it can still be churning away sending images to our app; if you go to the beta channel and sign up for beta builds of Pleco there's a new build up now that should fix that.
The lag only started after performing an OCR. Otherwise Pleco was fine. Sorry that I wasn't more clear.

I'm signed up for the beta channel now, and will be interested to share any findings.