interesting if you're using your 1 image of fullscreen size and you're moving it around don't expect on most phones more then 10 fps.
different phones have different graphics chips.
lumia & most androids - Adreno 200-400 - around 130 - 300M fillrate (pixels per second! )
iphone has PowerVR graphics - they have huge fillrates - 1G fillrate - even the old weak ones.
desktop PC - around 200+ Gtexels (but let's take the PC out of equation, everything will work on pc
so... you've created your graphics where you do something with your 854 x 480 single image
let's calculate the fillrate with that image:
853x480x32 = 13117440
now let's see how much fps can we get on each of our phones:
lumia and androids - with adreno (let's take the best one - 300M) = 300 000 000 / 13117440 = 22,87 FPS - on the strongest adreno, since you got ~ 10 fps, i guess it's adreno 200 which has 130M fillrate which gives us 130 000 000 / 13117440 = ~10 fps
iphone - 1G fillrate - 1 000 000 000 / 13117440 = ~76,23 fps - which is a good performance.
therefore conclusion - the problem is not your hardware, it's your game and the things you want to do. therefore you didn't really understand what ashley wrote in "not to waste memory" article..
also a bit more math - if you want to fill your space with moving objects - if they are 50x50 pixels - you can have them 1250 to work fluidly on every phone ~100M
the only thing i'm not sure 100% is if that is for 1 frame / s, or 60 frames /s, because if it's for 1, then for 60 you get ~ 21 object max