[dba-Tech] I've forgotten the numbers

Assuming an AMD dual-core processor and a Windows 7 or Ubuntu 64-bit, how
much RAM am I allowed to have? And is there a restriction on cores? All I
have at the moment is dual-core and 4GB RAM but I am willing to beef that up
to the max on both platforms. What is the max? I have a feeling it's 8Gb but
I have been wrong before and this would be no exception. 8 ought to suffice
for my humble needs, but just wondering. (Bear in mind that I have retired
from the field and am in it strictly as a hobbyist now. Not a lot of budget,
no active clients, just my meager pension to carry me through; if anything
costs more than $99 I probably can't carry it.)

TIA,
Arthur