Once in windows open up forceware control panel and set the gts450 for physx
i dont have forceware, but i used nvidia and that seems to have worked fine. just set the 450 as a straight physx card, and all good.
I'd sell all the cards and then buy one single monster...
considering ive only had the 560 for about 4-5 hours, i aint selling it any time soon. plus, my two 450's are my babies. they have done well for me since ive had them