Difference between RAM mount and AMPS?

Does anyone know the difference? Specifically, if my GPS bracket says its AMPs compatible will the RAM diamond mount work? Or is it that RAM works with all AMPs but not all AMPs fit the RAM? Or, just get the damn round AMPs and stop confusing myself?

I've never heard of an "AMP" mount. What brand of GPS is it? Maybe it is some kind of proprietary mount used only with that type of GPS?

Cycle Gadgets has a bunch of RAM mounts, maybe you can find one that works, or at least some more information about what options you have. http://www.cyclegadgets.com/Products/RAM/

They do list a AMPS Plate? But it says it is a mount for a Siruis Radio not a GPS...

AMP, from what I gather is an "industry standard" of mounting hole spacing. The AMP mount that RAM sells is round with a bunch of holes in it. Their diamond mount has two. I couldn't find the answer on the RAM website.