The cpu is just hicking continuously during working hours with a 15% load of traffic. Show process cpu indicates a high util which averages 85% but none of the process is suspect.
A bug scrub has not been helpful yet nor the document to reduce CPU interrupts.
See sample below
Cisco Internetwork Operating System Software
IOS (tm) C2600 Software (C2600-IPBASE-M), Version 12.3(5a), RELEASE SOFTWARE (fc1)
Copyright (c) 1986-2003 by cisco Systems, Inc.
Compiled Tue 25-Nov-03 05:59 by kellythw
Image text-base: 0x80008098, data-base: 0x80F002E0
ROM: System Bootstrap, Version 12.2(8r) [cmong 8r], RELEASE SOFTWARE (fc1)
HXCLS1 uptime is 1 year, 18 weeks, 3 hours, 52 minutes
System returned to ROM by reload
System image file is "flash:c2600-ipbase-mz.123-5a.bin"
cisco 2621XM (MPC860P) processor (revision 0x300) with 94208K/4096K bytes of memory.
Processor board ID JAE0813A7NP (2719836957)
M860 processor: part number 5, mask 2
Bridging software.
X.25 software, Version 3.0.0.
1 Ethernet/IEEE 802.3 interface(s)
2 FastEthernet/IEEE 802.3 interface(s)
32K bytes of non-volatile configuration memory.
32768K bytes of processor board System flash (Read/Write)
Configuration register is 0x2102
HXCLS1#sh process cpu sorted
CPU utilization for five seconds: 69%/66%; one minute: 66%; five minutes: 68%
PID Runtime(ms) Invoked uSecs 5Sec 1Min 5Min TTY Process
43 1872700 884154 2118 1.91% 1.52% 1.67% 0 IP Input
3 916 171 5356 1.27% 0.30% 0.08% 66 Virtual Exec
1 0 1 0 0.00% 0.00% 0.00% 0 Chunk Manager
2 960 9859 97 0.00% 0.00% 0.00% 0 Load Meter
4 48004 6504 7380 0.00% 0.03% 0.04% 0 Check heaps