[CentOS] Wield CPU load problem??

Recently we installed CENTOS 4.4 on DELL 2650 server. 
We found CPU load always on 3 and up if we run "top"
or "w" to check.  There is NO application run on this
server why CPU load so heavy?

=======   messages from check up   ===
%w
 11:31:56 up 20:02,  3 users,  load average: 3.06,
3.03, 3.00
USER     TTY      FROM              LOGIN@   IDLE  
JCPU   PCPU WHAT
oracle   pts/1    cdzppb1       10:14    1.00s  0.08s 
0.01s vim clone.sql
oracle   pts/2    tomcat2       10:46    5:13   0.05s 
0.00s login -- oracle                  
oracle   pts/3    hmh6b1        11:26    0.00s  0.04s 
0.00s w


%top|head -10

top - 11:32:09 up 20:03,  3 users,  load average:
3.04, 3.03, 3.00
Tasks: 109 total,   1 running, 106 sleeping,   0
stopped,   2 zombie
Cpu(s):  0.2% us,  0.1% sy,  0.0% ni, 99.6% id,  0.1%
wa,  0.0% hi,  0.0% si
Mem:  12196892k total,  8735360k used,  3461532k free,
   78508k buffers
Swap:  2040244k total,        0k used,  2040244k free,
 8348352k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM   
TIME+  COMMAND                                        
                      
    1 root      16   0  2564  528  452 S    0  0.0  
0:00.92 init                                          
                        
    2 root      RT   0     0    0    0 S    0  0.0  
0:00.00 migration/0                                   
                        
    3 root      34  19     0    0    0 S    0  0.0  
0:00.00 ksoftirqd/0                                   
                        


%sar -u 5 5
Linux 2.6.9-42.ELsmp       05/08/2007

11:32:26 AM       CPU     %user     %nice   %system  
%iowait     %idle
11:32:31 AM       all      0.05      0.00      0.05   
  0.05     99.85
11:32:36 AM       all      0.05      0.00      0.05   
  0.00     99.90
11:32:41 AM       all      0.05      0.00      0.10   
  0.00     99.85
11:32:46 AM       all      0.05      0.00      0.05   
  0.00     99.90
11:32:51 AM       all      0.00      0.00      0.05   
  0.00     99.95
Average:          all      0.04      0.00      0.06   
  0.01     99.89


%sar -q 5 5
Linux 2.6.9-42.ELsmp       05/08/2007

11:32:58 AM   runq-sz  plist-sz   ldavg-1   ldavg-5 
ldavg-15
11:33:03 AM         1       112      3.02      3.02   
  3.00
11:33:08 AM         1       112      3.02      3.02   
  3.00
11:33:13 AM         1       112      3.01      3.02   
  3.00
11:33:18 AM         1       112      3.01      3.02   
  3.00
11:33:23 AM         1       112      3.01      3.02   
  3.00
Average:            1       112      3.01      3.02   
  3.00


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