When one looks down the specifications sheet of a mobile phone he/she wants to buy, they usually come across the terms "CPU" and "RAM". These are supposed to be the terms we usually associate with desktops and laptops. Well, in today's technology, not much difference remains between a laptop and a mobile. All the terms that we used to associate with computers are now being used with mobiles.
Lets find out what CPU and RAM are doing in Mobile phones-
CPU-
This is the main Processing unit of a mobile. It carries out all the functions of the mobile from call to gaming. All the load goes to the CPU. It is responsible for the speed of the mobile. The speed of the CPU is measured in Hertz (Hz), the higher the clock speed, higher the number of calculations it can carry out in one second and therefore, higher the speed of the mobile phone.
However, there's more to it. Till now, the discussion was only on single-core CPU. There exist multi-core CPUs. In simple terms, they are like more than one single core CPUs bundled together. For mobile devices that support multi-tasking (an arrangement where one or more applications keep running in the background while another application is run in the front that gets to utilise the display), a dual-core CPU (a CPU with 2 cores) or quad-core CPU (a CPU with 4 cores) can greatly boost performance. Software that is optimised for multi-core CPU also benefit greatly from it. While dual-core CPU for mobile devices are already available (though for a high price), quad-cores are not yet in mass-production stage.
One more specification for a CPU is its ISA (Instruction Set Architecture) or simply architecture. Almost all mobile CPUs are of the ARM architecture, which is an RISC (Reduced Instruction Set Computer) architecture. ARM Cortex A is the latest family, before them there was the ARM11 family, which is older but is still used in lower end devices. ARM Cortex A9 is the latest processor that gives high performance while consuming less power. ARM Cortex A8 was released before that which gives way better performance than the older ARM11 cores and is found on most high-end smartphones currently selling in India. ARM Cortex A15 is currently in pre-production stage, but it promises performance even better than the Cortex A9. ARM 11 family's ARMv6 processor is a low end processor that supports clock speeds upto 667Mhz and used in budget smartphones and media players.
In short for processors with same clock speed and number of cores,
ARM Cortex A9 > ARM Cortex A8 > ARMv6
RAM-
RAM is a term with which most of the people who own a computer or a laptop must surely have heard of.
It is the parameter which decides how many apps can run simultaneously on a mobile phone without the phone going to a breakdown. More RAM means more space for programs to run and therefore more smooth will be the functionality of the mobile. Also without large amount of free RAM it would be difficult to play large, graphics-intensive, real sounding games.
The RAM of a mobile has increased with time. Older mobiles used to have 16-64 MB of RAM whereas today's high-end smartphones employ 256 MB, 512 MB or even 1 GB of RAM.
Another important specification of RAM is speed. A RAM with high speed is needed for a CPU to perform its best. Usually, a system gives optimum performance if its CPU's and RAM's speeds are equal. If either one is lower, it "bottlenecks" the other.
One more thing to note about a mobile system's RAM is whether it's DDR1 (referred to as just DDR) or DDR2, both of these are types of DDR SDRAM (Double Data Rate Synchronous Dynamic RAM). DDR2 has lower power consumption and higher performance that DDR1 (or only DDR). DDR3 are not available in mobile devices yet.
While going for a handset, these are the two primary things one needs to take care of as today's OS such as the Android, and iOS are quite heavy and require high clock speed and RAM for their full fledged functionality.
