DDR2 Has High Density And Low Density Like DDR?

[Redhatcc]

i know that regular ddr memory has high density and low density, and most of the time if you get high density ddr ram it wont work unless you have the correct chipset/motherboard that will support high density.

well i was looking on ebay and there are sellers that are selling ddr2 high density sticks and ddr2 low density sticks....

i was under the impression that ddr2 was all high density? and that all ddr2 motherboards would support generally any ddr2 stick.