Within Server 2008 it is possible to limit a user a specific percentage of CPU Time.
Lets assume there is a Backup Service Account. This account makes every night a backup. The creation of a backup is time consuming process (depends on amount of data) and there is a requirement from the business that it may not prohibit the business from functioning.
1. To make a change in the registry you need to determine the sid of the user account.
Open a command prompt and type in: wmic useraccount get name,sid
2. Create in the registry a directory named after the Sid.
open cmd (* with elevated rights!)
reg add HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Quota System\S-1-5-82-3006700770-424185619-1745488364-794895919-4004696415Replace the sid (S-1-5-***) with your backup account sid. 3. Open registry en go to location open the registry regedit then browse to the following directory: HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Quota System\S-1-5-82-3006700770-424185619-1745488364-794895919-4004696415 4. Under this key, create a new REG_DWORD value CpuRateLimit and set its value to the percentage you wish. (For example 70%) 5. A reboot may be required for changes to make affect. This will limit all the processes running under that account SID to use only 70% of the CPU.Source Article: http://technet.microsoft.com/en-us/library/ff384148%28WS.10%29.aspx