What's the Difference between Microsoft Volume Licensing Open License Program (OLP) vs. Original Equipment Manufacturer (OEM) for Server Products?

Windows Server OEM Licensing


OEM Licensing covers up to 16 processor cores per machine. Even if your machine has less than 16 cores, you must license the minimum of 16.


OEM licenses do not include transfer or downgrade rights, and if you have begun an active SAM audit, you typically are not allowed to purchase additional licenses to become compliant before the audit is complete. 


In a scenario where you have more than 16 cores but less than 32, the OLP licensing would end up being less expensive overall. OLP licensing is sold as 1 license for every 2 cores, so you have 20 cores total, it’s cheaper to buy 10 OLP licenses than 2 OEM licenses. 



  • Lower upfront cost than OLP
  • Comes in sets of 16 core licenses
  • No Transfer Rights
  • No Downgrade Rights
  • Purchase may not be accepted during an active S.A.M. audit


Microsoft Volume Licensing Open License Program (OLP) Licensing


OLP licensing is sold as a 2 core license covering 2 processor cores of your machine. Just like the OEM license, the minimum licensing required is still 16 cores, so you will need to purchase a minimum of 8 OLP licenses. 


If you have 16 or less cores on your machine, it’s typically less expensive to get a 16 core OEM license rather than 8 individual 2 core OLP licenses. 


Although OLP is more expensive, there are a few key benefits to OLP over OEM, including transfer rights, downgrade rights, and the ability to purchase additional licenses to become compliant during an active SAM audit. 



  • Higher upfront cost than OEM
  • Comes in sets of 2 core licenses
  • Includes Transfer Rights
  • Includes Downgrade Rights
  • Purchases accepted during an active S.A.M. audit