Greetings !
[quote:bp0f3ipg]what are the main elements that consume performance in mobile?
Unfortunately this varies A LOT depending on the make and model ; it is not unusual to have mobile devices of the same "family" being completely different internally from an architecture point of view.
On some platforms, memory reads are very expensive, therefore it's better to have less texture reads and more interpolator work done in the shaders. On some other platforms, it's exactly the opposite, where pixel units perform very badly but memory is fast, in which case you want more texture reads and less load on the interpolator. Typically optimising for one set of devices is counter-productive to all the other ones.
Same with alpha blending, which can be a killer on many devices. Pretty much the same can be said about every feature :/ Which is why developing for mobiles is a pain... For "big" games, each category of devices ends up being its own platform port.
A benchmark would need to test a bit of everything, but look mostly at memory (loading lots of resources), blending (overlapping alpha-enabled sprites), fillrate and overdraws, and shaders.
A couple of links for a general performance overview :
androidbenchmark.net
iphonebenchmark.net
These are quite reliable and are useful to check in which "band" a given device is.
'Hope that helps.