For the 32-bit version, that number will have to scale down to 6 and 12. Hyper-v: On a 960 MB per instance setup, I can run 8 instances just fine on a 12 GB ram machine, or 16 instances on a 16 GB ram.
If all you need is 1-2 instances these numbers are not matter. From my experience, Hyper-v seems to boost on faster and use a bit fewer resources, when comparing to the 32-bit version.
I run bluestacks in 4-5 servers with 24-35 instances depend on the time.
