The iPad 1 has the same 256MB of RAM but it has to allocate more than double the amount of space towards VRAM than a 3GS. Also in general iPad applications have

The iPad 1 has the same 256MB of RAM but it has to allocate more than double the amount of space towards VRAM than a 3GS. Also in general iPad applications have a larger memory footprint than iPhone applications. Those two factors combined pretty much doomed it. Most importantly Apple just decided to starve it of RAM. Very bad design choice.