Knowing about performance impact of simple use of procedures

If you ask an experience DBA about the reasons for performance loss then the answer should be straight to look for SQL Server, Operating System and hardware counters for further investigation. Simultaneous access to shared resources causes bottlenecks. In general, bottlenecks are present in every software system and are inevitable. However, excessive demands on shared resources cause poor response time and must be identified and tuned. The main root causes of bottlenecks include: Insufficient resources, requiring additional or upgraded components, resources of the same type among which workloads are not distributed evenly; for example, one disk is being monopolized & malfunctioning resources. Also many times the incorrectly configured resources will have the impact too.

Round trips from client to server to client will have impact eventually, due to the excessive durations for various events are indicators of bottlenecks that can be tuned by looking at your code. Performance loss investigations should start from disk & memory, as the insufficient memory allocated or available to SQL Server engine degrades performance. Data must be read from the disk rather than directly from the data cache. TSQL queries can be tuned to reduce unnecessary I/O, such as adding sensible indexes;

Like above there are various reasons to investigate for such performance loss, but even sometimes the performance will be at 'major' loss. For instance when a stored procedure is called in general it will be called with the name without mentioning the qualifying owner name. To dig deep into further refer to the exciting blog posts by Linchi Shea on SQLBlog website:

Performance Impact of Procedure Calls without Owner Qualification

Performance Impact of Procedure Calls without Owner Qualification -- SQL Server 2000

Performance Impact of Using NTFS Compression with Read-Only Databases  - this one comes as a surprise if the proper configuration of hardware is missed or ignored.