Well, just to clarify, the motherboards ARE limited by the BIOS if you haven't upgraded them. And I know certain ones physically don't support quad-core CPUs (or, I suppose, CPUs of a certain TDP) so there are differences.
I assume mobos with only 2 DIMM slots could only do 2 x 2GB for 4 GB max so you'd be limited by that, too. I don't know why the 530 would have different memory support than the 530a/530c and I'm hopin' you'll be fine regardless.
Looking again more carefully, the 530 (non a/c) is the only one with a floppy connector next to the power connectors. So if you have a floppy connector, you might be hosed. Only one way to find out, though.