In SharePoint 2010 or 2013 For better performance Microsoft SharePoint set some default or minimum value for its resources. E.g Resource Throttling value set to some default value if you want to increase or change some other value you can manage it through powershell script.
SharePoint 2007 - 2000 max items returned by a list view.
SharePoint 2010 - millions of items. but List View Threshold Minimum default is 5000.
if you try to change it more than that 5001, you will get message "Number of items in this list exceeds the view threshold, which is 5000" Central Administration -> Application Management -> Manage Web application
Web application -> Click on the Ribbon and click the General settings Dropdown -> Select Resource Throttlling Maximum number of items in a view for a user who has sufficient permissions - Default is 20000


function UpdateThrottlingonWebApp
    param (
            [parameter(Mandatory=$true, Position=0)]
            [parameter(Mandatory=$true, Position=1)]
            [string]$ListViewThreshold, #List View Threshold
            [parameter(Mandatory=$true, Position=2)]
            [string]$ListViewThresholdForAdmins, #List View Threshold Admins
            [parameter(Mandatory=$true, Position=3)]
    $spwebapp = Get-SPWebApplication -identity $webAppName
    $spwebapp.MaxItemsPerThrottledOperation = $ListViewThreshold
    $spwebapp.MaxItemsPerThrottledOperationOverride = $ListViewThresholdForAdmins
    $spwebapp.MaxQueryLookupFields = $MaxLookupFields #List View Lookup Threshold
    Write-Host "Throttling settings value has been updated on" $

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