Is there a way to set via GPO:

1) The event logs on all my servers to overwrite events every 7 days?
2) For the desktop performance of each interactive user to be set to "Best
Performance"
3) For the page file to be set to "System managed size"

1.  Computer Configuration\Security\Eventlog
2.  No default setting exists but you can create a custom policy to set the
registry the following registry key:

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\VisualEffects\VisualFXSetting
registry subkey. The default value of 0 is Let Windows choose what's best for
my computer. Change the value to 1 for Adjust for best appearance or 2 for
Adjust for best performance

3. No default setting exists but you can create a custom policy to set the
registry following registry setting

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory
Management registry subkey. If you want the system to manage pagefile size,
simply set the initial and maximum pagefile sizes to 0, as the following
example shows:
C:\pagefile.sys 0 0

Tutorial to create custom policy
http://support.microsoft.com/kb/323639
To view the custom policy in the GPO editor go to administrative templates
right click, choose filter: disable show only policy that can be fully
managed.

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