I recently purchased a Mac Pro (late 2013) and discovered that the Energy Saver Pane is a little different; most notably, the Computer Sleep slider is missing. Here is how to get it back.
First, use the following terminal commands to determine the model and board ID of your computer:
sysctl hw.model | awk '{ print $2 }'
ioreg -l | awk -F\" '/board-id/ { print $4 }'
Second, navigate to the following folder:
cd /System/Library/Extensions/IOPlatformPluginFamily.kext/Contents/PlugIns/X86PlatformPlugin.kext/Contents/Resources/
Third, determine the .plist file that corresponds to the model and board ID of your computer; e.g., Mac-F60DEB81FF30ACF6.plist.
Fourth, modify the file that corresponds to the model and board ID of your computer:
sudo vi /System/Library/Extensions/IOPlatformPluginFamily.kext/Contents/PlugIns/X86PlatformPlugin.kext/Contents/Resources/Mac-UDID.plist
Fifth, change the following line:
to
Sixth, regenerate kext cache by “touching” the Extensions directory:
sudo touch /System/Library/Extensions
Finally, wait a minute just to make sure the system has enough time to finish regenerating the kext cache. Then, reboot your mac.
Alas, you will once again have the two-slider pane.

five Mac OS X Snow Leopard Tweaks I Can’t Live Without
27Feb111.) Always view Mail.app attachments as icons.
Restart Mail.app, and voila!
2.) Use a spacer to split the Dock between Docked applications and non-Docked applications.
3.) Add one or more stacks of recently used items.
4.) Enable new List view in Dock Stacks.
5.) Enables gradient effect on mouse over.