Although heavy-duty hardware can help SQL Server's performance, application and database design can play a greater part in the performance than hardware . Keep this in mind as throwing good money after bad on server hardware does not always fix SQL Server performance problems.
Many people assume that the server hardware they work with is installed and configured correctly.
This can be a costly misjudgment. While the hardware may continue to run in spite of problems, performance problems may lurk beneath the surface. Always verify that the hardware and drivers are current and properly configured. I have seen cases where SCSI cards have been misconfigured, causing data corruption. I have also seen outdated, buggy RAID drivers causing data corruption.