It can't, it can only support 3.5GB of RAM.
2GB is pretty much optimal... in any case, you shouldn't give a virtual machine more than Total System RAM / Number of CPU Cores worth of RAM. Software virtualisation cannot take advantage of more than that, and even with a Hyper-V you won't really be able to take advantage of the additional RAM fully.
It can only address 3.5gb of RAM. You can install 4gb though.
It can only address 3.5gb of RAM. You can install 4gb though.