nvidia Physx problem

I just got a new Desktop its a intel i5 655k 3.2ghz I just installed a Radeon HD 5850 graphic card it runs perfect I can max out everything thrown at it but I bought a couple of games that have Physx Metro 2033 and cryostasis these are the only games my card struggles with maxed out with physx on, I was wondering should I step over to the darkside and commit to nvidia or should I stay with my beloved ati radeon. Things like this is why I hate nvidia they know ati is winning over PC owners so they get slick and tell game developers to make a way to get Pc owners to crossover to their product. Ati or Amd radeon do the same thing develop your own physx superior to nvidia's and crush them for good!!!!!!!