License Upgrade

I'm having trouble finding any answer to this question on any spec sheets.

 

With moving forward with buying a new unit I'm looking at a unit with the option to upgrade the license.

 

If I have an i5600 with a license upgrade option to i5800, what is exactly being upgraded via the license?

 

On the Spec Sheets I see the L7 and L4 connection counts are increased at what threshold limits they are allowed.

 

The hardware remains the same, no physical boxes are being upgraded.

 

In this example are the i5600 boxes just purely limited in the connections they are allowed L4 and L7?

 

The boxes are running on the same hardware, but does F5 restrict the 48 GB of Memory I'm utilizing on an i5600, IE limiting me to 24 GB of memory opposed to the full 48?

 

I see some old posts here where it's confusing as well, where people feel they are unlocking hardware, ie memory or cpu.

 

Is anyone able to confirm what is and what is not unlocked with licensing upgrading.