Other way around.
Demon souls was the PS3 exclusive, dark souls was on PS3 and Xbox 360.
EDIT : See, when Alan Wake got a PC release, Remedy did that properly, bar a few low textures I could forgive it was perfect for me, a very good game, nice graphically etc.
But this? Urgh.
Remedy did everything right, From are doing everything wrong.
Weird thing is, they ported Ninja Blade to PC and it ran fine, I'd say they are about equally demanding hardware wise, with Dark Souls just edging forward. They can't really use the never ported before excuse because they have, if it runs worse than console versions I won't touch it, if its about the same/abit better I will get it(providing the bloody DLC doesn't get bad framerate too).