The Windows 7 Home Premium EULA does not specifically place a restriction on physical memory. However, it does mention that unauthorized changes invalidate your license:
§ 5.C. If, after a validation check, the software is found to be counterfeit, improperly licensed, a non-genuine Windows product, or include unauthorized changes, the functionality and experience of using the software will be affected... 1
If you research the matter, you will find that groups have already made efforts to circumvent the memory restrictions in Windows 7. In summary, these methods require unsupported, unauthorized modification of systems files -- some specifically related to licensing -- in one way or another.
My advice would be to go with Windows 7 Professional, since the Enterprise and Ultimate editions also have a 192 GB limit on RAM. 2 The only main features you would be missing would be BitLocker and extended language support. 3
References:
Windows 7 Home Premium EULA
Note: If the link expires, visit Microsoft | License Terms to download the EULA.
Physical Memory Limits: Windows 7
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