Could be the following defect:
CSCdy78397
AMDP2_FE-3-RXOVERFLO msg severely degrades performance on 2600
First Fixed-in Version 12.2(12.10)T01, 12.2(13.3)B, 12.2(15)BW
If running code less than the fixed version you might need to upgrade.
Hope this helps you,
Don