This message was posted on behalf of Intel Corporation
I understand you would like to know if the Intel i7-3770 CPU supports or not Windows 10* 64-bit.
Let me apologize for any inconvenience this issue may be causing to you.
The processor itself supports Windows 10* 64-bit, but depending on how Dell* configured the whole system then the operating system that will run in that specific system.
The best option would be contacting Dell* in order to check if that specific system will be able to support Windows 10* 64-bit.
Let me know if you have or not any other inquiry.
Problem solved, System can run 64bit Win10, needed to boot system into bootable install media then I had to manually wipe the drive and convert it to GPT (Windows Setup: Installing using the MBR or GPT partition style) then was easy to install.
now I have all my RAM usable