In line with the new Microsoft whitepaper and in relationship to the many questions I receive on this topic, I thought I'd take a second to discuss Hyper-V and SQL Server with Dynamic Memory.
"Can I use dynamic memory with SQL server?"
If you are running SQL Enterprise or Datacenter editions that support hot-add memory, yes you can use dynamic memory.
This is because SQL server is able to adapt to the addition of memory on an "on demand" basis and is able to make use of it. SQL Server Standard edition cannot.
I've run into this many times, where a customer has configured dynamic memory for a version of SQL that does not support it and has very strange results. In this case the support statement exists because SQL Standard specifically does not support the technical requirement to make use of the dynamic memory allocation, whereas enterprise and datacenter editions do.
Here is the reference to hot-add support for memory in SQL server:
"Will dynamic memory with SQL server be better than not using it at all?"
Yes. It certainly will. Here is a great whitepaper that addresses SQL Server and Dynamic Memory in Hyper-V:
"What is the support policy with SQL Server virtualized in the first place?"
Here it is: