How do I Improve my server performance expert guidance required
 

top - 10:31:20 up 101 days, 21:06, 6 users, load average: 0.37, 1.39, 1.58
Tasks: 1312 total, 1 running, 1311 sleeping, 0 stopped, 0 zombie
Cpu0 : 4.6%us, 1.0%sy, 0.0%ni, 90.4%id, 4.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu1 : 3.9%us, 0.7%sy, 0.0%ni, 95.4%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu2 : 2.9%us, 0.3%sy, 0.0%ni, 96.7%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu3 : 2.6%us, 0.3%sy, 0.0%ni, 97.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu4 : 3.0%us, 0.3%sy, 0.0%ni, 96.7%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu5 : 4.9%us, 1.0%sy, 0.0%ni, 93.8%id, 0.0%wa, 0.0%hi, 0.3%si, 0.0%st
Cpu6 : 3.3%us, 1.6%sy, 0.0%ni, 95.1%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu7 : 1.3%us, 0.7%sy, 0.0%ni, 98.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 32435760k total, 31576232k used, 859528k free, 21300k buffers
Swap: 16482296k total, 2381696k used, 14100600k free, 23684516k cached

You need to give us more info. For example what kind of system/os you have? What was installed? Why do you think you need to improve anything. What do you really want to improve?
Based on your info I cannot say anything, it looks ok (just you have more than one thousand processes).

System Dell PowerEdge 830 Server
OS CentOS 6.3
Database PostgreSQL 9.2
Application PHP ,boost Framework, GCC

I need to utilized Maximum resources on DB side

Is there any bottleneck on memory or CPU level?

Do I need to execute vacuum command on daily bases?

what if I reduce Swap and increase memory ?

Is it? As far as I can tell it cannot be a PowerEdge 830, they are single or dual core, not 8 cores or 8 threads.

http://www.dell.com/downloads/global.../830_specs.pdf

There is always some bottlenecking.

You might get something with increasing RAM....decreasing swap size will not help performance.

Yes It is Dell PowerEdge 830 Server
It contain 2 processes but unfortunately one processor was not working so currently it is operational with its single processor.

by analyzing Top command how would you say it is single or core2due

One more thing is there any command you know that share resources among multiple cores

Core2Duo is a type of dual core Intel CPU. It only has 2 cores, 2 threads.

'Dual core' can be appled to any CPU with 2 cores, like Pentium D, Athlon 64 X2, etc..

That shows either 8 real cores, or 4 cores/8threads with hyperthreading.

Power Edge 830 is single CPU socket only, no dual CPU versions.

Icant see any way your top readout can be from a power edge 830.....besides having too many cores, its got way to much RAM. Power edge 830 has a 8GB maximum, that appeas to have 32GB.

You can try atop and the likes and have a look for other ressources than CPU load and RAM usage. You might find your HDDs being busy all the time but only doing a few MB/sec because of constant seeks or something else.

If you think its disk related (& with a DB it could be), try http://linux.die.net/man/1/iotop & http://linux.die.net/man/1/iostat.
Really though, you have to narrow down exactly what is slow; could easily be crap code/incorrect indexes on the DB.