There are many tools for yuor requirement you can try any of these as
per your requirements
Overall system statistics screen you will get with "topas" command

To view the screen that lists the busiest processes, use the -P flag of
the topas command.



"vmstat" - Reports virtual-memory activity and other system statistics.

# vmstat 2 10
Remember that the first report from the vmstat command displays
cumulative activity since the last


Kthr: Kernel thread state
r :Number of kernel threads waiting in run queue. This value is zero in
an
idle system and higher in a CPU bound system.

b Number of kernel threads waiting on the wait queue (awaiting
resource,
awaiting input/output).

Memory: Usage of virtual and real memory
avm :Active virtual pages, that is, the total number of pages allocated
in page
space. A high value is not an indicator of poor performance.
fre :Size of the free list RAM pages

The vmstat -s command The summary option,

The ps command can also be used to monitor memory usage of individual
processes.
The following is an example:

# ps v
PID TTY STAT TIME PGIN SIZE RSS LIM TSIZ TRS %CPU %MEM
COMMAND
36626 pts/3 A 0:00 0 316 408 32768 51 60 0.0
0.0 ps v

RSS Real-memory (resident set) size in kilobytes of the process. This
number is equal to the sum of the number of working segment and code
segment pages in memory times 4. Remember that code segment pages are
shared among all of the currently running instances of the program. If
26 ksh processes are running, only one copy of any given page of the
ksh executable program would be in memory, but the ps command would
report that code segment size as part of the RSS of each instance of
the ksh program.


The svmon command can only be executed by the root user.

The svmon -P command displays the memory usage statistics for all the
processes currently running on a system. The following is an example of
the svmon -P command:
# svmon -P

svmon -G -i 1 2 --- Amount of memory in use