Thanks for replying.
I'm just trying to create a Lab environment with 3 vESXi's so I could play around with them and VC and complete all of the objectives of the VCP and VCAP exams (my courses is 2 months from now) the VM's will be 64bit windows R2 with exchange 2007-2013, SQL 2008-2012, SCCM and such and as i said the pESXi will be the following server : HP 380 G6 with 72 gb of ram x2 X5570 and a P410i 512MB controller.