When you buy a Microsoft product of any kind, it will come with a summary of technical limitations which will enable the software to work in specific ways - even though these limitations are no longer included in the Product Use Right documentation - they cannot be ignored.
Each product has its own set of capabilities as well as licensing guidelines for its use. There is a great table available here that should answer many of your questions as to what you can do with each product.
Details such as how many processors are being run on your Microsoft product will affect its licensing requirement and must be taken into account should the need arise to make any changes.
One more thing to be on the lookout for when preparing your software asset management plan.