There are some of the points about the Report and Dashboard Limitations, and these apply to all supported editions:

• We can create a dashboard only from the matrix and summary reports.
• A report will display the maximum of 2,000 rows. All the rows will be displayed by exporting the Report to Excel, or by using the printable view for summary and tabular reports. For joined reports, the export option is not available, and the printable view displays a maximum of 20,000 rows.
• In the report builder, up to 20 rows will be displayed for summary and matrix reports and up to 50 rows for will be displayed in the tabular report.
• You can use five formulas per report.
• You can use up to 20 field filters in a report.
• To set the maximum number of records to display in a tabular report, click on Add and select Row Limit in a report builder.
• By default, reports timeout after 10 minutes. You can contact Salesforce.com support to extend the time-out limit to 20 minutes for tabular, summary, and matrix reports, but no extension is available for joined reports. It will continue to time out after 10 minutes.
• Reports will show only the first 254 characters in a rich-text area or a long-text area.
• Summary fields on the summary, tabular and matrix reports can display up to 21-digits.
• Reports cannot be filtered on custom long text area fields.