find memory utilisation of processes in AIX

For memory information, I think you want svmon.

svmon shows the total usage of physical and paging memory

svmon -P -v -t 10 | more

(will give top ten processes and user)

Displaying top CPU_consuming processes:

ps aux | head -1; ps aux | sort -rn +2

Displaying top memory-consuming processes:

ps aux | head -1; ps aux | sort -rn +3 | head

Displaying process in order of priority:

ps -eakl | sort -n +6 | head

Displaying the process in order of time

ps vx | head -1;ps vx | grep -v PID | sort -rn +3

Displaying the process in order of real memory use

ps vx | head -1; ps vx | grep -v PID | sort -rn +6

Displaying the process in order of I/O

ps vx | head -1; ps vx | grep -v PID | sort -rn +4