Jerky Performance

I have created my game in Construct2 but one issue I have is every 4 seconds or so the sprites jerk slightly in the game. There are only 5 or 6 sprites on the screen.

I have also reduced the collision points to the absolute minimum - between 4 and 6.

Each sprite is 120x65. There are 5 frames repeating at a speed of 7 but even with just 1 frame it still jerks.

No particles/effects/scale/flip/blend modes used.

I have tried everything to reduce this and it occurs on my PC in Firefox (or IE). Same issue on my iPad (iPad4 - 1024mb RAM, retina display).

Using the CocoonJS app I get 62FPS. I have built the game in the Cocoon cloud and the issue is also there.

I am using r139 64 bit, OpenGL 3.3.11672.

The game - download size 19.3 mb, memory use 158mb (was 173mb but after optimizing I have it down to 158).

Background image - 122kb

Layers - 4 (bg, main, HUD, Touch controls)

Use loader layout - No

Pixel rounding - On

Preview browser (default)

Fullscreen in browser - Scale

Use iOS retina display - All devices

Enable WebGL - On

Sampling - point

Clear backgrround - No

My PC - Win 7 64 3Ghz, 3Gb RAM, ATI Radeon HD 4800 (latest driver).

So I'm stuck right now - please help!

can you post a link/cap of your game?

you need to provide more info because it could be just a simple image point misplaced on one of the frames or something off scirra engine, like a extension is being loaded behind your browser, causing it some sort of lag...

Are you using bullet behavoir or bounce? I had something similar in a game I am making using Cocoon. Lags when objects bounce =( I have not found a fix yet

I've been trying to narrow this down....

My game features pretty much just two sprites on each layout - player and enemy. The same enemy is just spawned again. I have switched enemies from different layouts and it seems not to be an issue such as an image point with a sprite.

As mentioned it happens with the browser, in Cocoon launcher and in my Cocoon built app so its coming from Construct2 as not all the devices can be at fault.

I am using bullet behaviours - will try some sprites without them and see what happens.

No it happens with sprites that just use Custom Movement also.