Opera - it has the smallest RAM footprint and since a lot of it is written in optimized assembly language, it's also very fast. It also adopts a few tricks adopted by Apple (in it's rules for iPhone apps) which basically means that any element not actually visible will be unallocated,
People may have noticed that Opera appeared on things like the Gameboy Advance & Nintendo DS - platforms with far fewer resources than a desktop or even a modern smartphone.
I don't know what, if any extra benefits other browsers bring to the table but I'm acutely aware that they seem to allocate a lot of resources and retain them. I don't KNOW but I presume that they take all of the resources that they potentially might need and hold onto them. This IS how MOST PC apps are written and it's simply bloatware. If the price or RAM suddenly went up by a factor of 10, a desirable feature of ANY application would be that it shares resources instead of just grabbing everything.
Lastly, since only 3% of users use Opera, it's unlikely that malware would ever target it*
*Of course, ARM patented 'Chameleon Code' which uses some algorithm (possibly based on the CPU ID) to produce unique code for every single copy of software using it. Logically it does the same things BUT since the 80x64 CPUs are orthogonal and RISC-like, it means ANY of the 16 x 64-bit registers can be used in every instruction. I have to admit that the trick would struggle to be implemented on the older, 32-bit CPUs since they have half as many registers and certain instructions can only be used with certain registers.
