a) Minimum basic requirement - 512MB of RAM
b) Recommended hardware requirement - 2GB of RAM
To create a hardware profile, follow the step by step instruction
1. Click on Library View and on the Library Action ,select New hardware profile.
2. A new hardware profile page is open. On the General tab, enter the name.
3. Click on hardware setting tab and specify the hardware for minimum and recommended hardware. For my scenario is
a. Minimum hardware - 512 MB RAM
b. Recommended hardware - 1024 MB RAM.
Repeat the step 1 -3 and create the profile
You've just created 2 profile which you're going to use when creating new virtual machine.