SQL Server - Difference between Insert and Update

I have thousands of records in few tables. I have written a stored procedure to retrieve and update records in my table,

Actually performace depends on the total number of records of table and WHERE clause of UPDATE statement.

So check this link which will tell you some hints for improving performance in case of update;

http://searchoracle.techtarget.com/answer/Improve-performance-of-SQL-query

http://www.tek-tips.com/faqs.cfm?fid=767

if u think ur job can do with case then i will say to use case 

Currently i am testing the query with 10 records. But the query actually has to run in an environment where there will 7Lacs + records

hi,

in order to increase the performance, add index in your tables with the fields often used in the 'where' condition

u r updating the same table by using the 7 query?

then u can write a single update query.

check the below query for example

update myTable set  field1='value1'  , field2='value2' where id = 10

Thank you