The maximum number of controls allowed on MSCRM dashboards are 6. You cannot put the more than 6 graphs/charts/iframes/webresources etc. on the dashboard.
This setting is applied to the server not a organisation setting. So you cannot change this setting for CRM Online but you can change this for an on-premise installation.
There are two ways to do it.

1. Using Deployment Web Service (http://myservername/xrmdeployment/2011/deployment.svc)
2. Using Window Power Shell

Windows Power Shell Option is the easiest one.

• Open the Windows Power Shell
• Add the Microsoft Dynamics CRM PowerShell snap-in using

Add-PSSnapin Microsoft.Crm.PowerShell

you may get the message saying something like “Add-PSSnapin : Cannot add Windows PowerShell snap-in Microsoft.Crm.PowerShell because it is already added.” It is okay.

• Run the following 3 command

$setting = Get-CrmSetting -SettingType DashboardSettings
$setting.MaximumControlsLimit = 8 (// you can change this number)
Set-CrmSetting -Setting $setting

Here is my screen shot with 8 charts.

Setting：

View：

引用地址：http://www.cnblogs.com/Earson/p/MSCRM_Dashboards.html