can't stick more than 16GB of RAM on motherboard

[HoneycombAG]

Unless I do a Windows Anytime Upgrade, or unless I can get rid of this jet-engine of a CPU cooler, I can't stick more than 16GB of RAM on my motherboard anyway. So what gives?
This motherboard supports up to 64GB.

 

[derekimo]

Unless I do a Windows Anytime Upgrade, or unless I can get rid of this jet-engine of a CPU cooler, I can't stick more than 16GB of RAM on my motherboard anyway. So what gives?
This motherboard supports up to 64GB.

You pretty much answered your own question.

Home Premium x64 has a 16GB limit.

Memory Limits for Windows and Windows Server Releases (Windows)

 

[LMiller7]

On any computer there are going to be 2 factors that limit how much RAM you can use:

1. Hardware. The RAM that can be installed on the motherboard, subject to physical constraints.
2. The OS. How much RAM can the OS recognize. On modern operating systems this is usually a licensing restriction and no legal way to circumvent it.

The usable RAM will be the smaller of the two. It could not be otherwise.

Lower editions of Windows must have limitations not found in higher editions. Otherwise who would pay the higher price of the latter?

Of course you could upgrade to Windows 8 which has a RAM limit of 128 GB, 512 GB for Professional and Enterprise editions.

Memory Limits for Windows and Windows Server Releases (Windows)