Large FPS drop/Lag on Feb 2014 UDK?

[mhinge]

I'm posting because we just upgraded to the newly updated Feb 2014 UDK (for iOS7 support). We were previous using Nov 2012, and we're experiencing very dramatic lag/FPS drop after updating. In particular, on the lower RAM devices, esp. iPhone4S and non-retina iPad mini (we're not planning on supporting below 4S, or below iPad2). The iPhone4S I'm using for testing was already on iOS7. When upgrading from iOS6 to 7, we had some initial problems with it crashing, but reduced content loaded during the game, and had since been able to play through without crashing, and with good FPS. Until upgrading UDK to Feb 2014 this week. Now it's to the point where audio and animations no longer sync up much of the time, and it staggers a lot (where animation lags behind the audio). We've gone through the config settings to double check no expensive mobile features are on, and to the best I can tell, they aren't.

Most of our devices are still on iOS6, leftover from wanting to be able to use console commands. Spot testing on iPad4 and iPad3 (still on iOS6 though), seem to show they still run well FPS-wise. While I didn't personally see it, I've been told the same FPS issues also happen on non-retina iPad mini on iOS7.

Have others experienced anything similar, and does anyone have any advice?

[HEGI]

The FPS drop i experienced going from July 2013 > Feb 2014 is minimal. Did you reduce the content scale factor and disable lightshafts and gamma correction ? You can also try to set high resolution timing to false on devices prior to iPad Air and iPhone5.

[mhinge]

We've gone through, and double checked that all the settings for the devices were the same as before, which included not having gamma correction on. We also tried reducing the content scale factor from what it was in Nov 2012 build and it hasn't resolved.

Furthermore, what's happening is: On initial deploy, after not using the device for a long period, I get through about 20 minutes of the game with good FPS. Once hitting the point of lagging, I tried starting the game from the beginning. And on that playthrough, the FPS dropped significantly, even though it was fine on the first playthrough. We have streaming levels, but I used 'stat levels' to check that the appropriate ones were loaded/unloaded, which they were. Even more, I completely deleted the app from my phone, and did a redeploy. The game had low FPS right from the start, despite this. Only when I completely turned my phone on/off, and then redeployed, did the game return to the high FPS at the beginning.

[HEGI]

This sounds indeed weird. Did you try not to use level streaming at all ?

[mhinge]

I have a belated reply to this... where it's solved... sort of.

To answer the question, we have too much content to not use level streaming. It's a very linear story based games, with lots of custom animation, audio and so forth, and splitting it up is necessary, or there would be far too much to have loaded at any time.

The iPhone4S I was using was on iOS 7.0.6. After trying many things, on the off chance, I upgraded to 7.1 (with and reverted any attempted changes to code/config/content), and now it's back to how it was before. Frame rate decent, and there's never a sudden change after playing a while (was able to play through all of our content without issue). I also tried on iPad Mini with 7.1, and it ran fine there as well.

On the one hand it's great that it works. On the other, if there's no solution other than downloaders needing 7.1 or above to not have issues, it seems like we risk the ire/confusion of app store users. It's also very strange to us, that given an Unreal-unrelated iOS update fixed, that no one else seems to be having the same issues prior to 7.1. If it was a pre 7.1 iOS memory leak issue, it seems like others would also be having problems.