GTX 660Ti vs GTS250

I know I should expect an monstrous fps and graphic quality increase.
My question is, should I keep my GTS250 in an secondary slot as an Physx card or it's not worthy.
Second question, to keep it as an Physx card do I need to have the SLI bridge on?
How much would that hit my performance?
I'm using an Gigabyte 990XA-UD3.
Got a 16x / 8x / 8x PCI-e setup.

 

don't use the 250 for physx. if anything it'll make things slower.

 

I guess I'll end up buying an glass portrait and hang my GTS250 on the wall.
5 years overclocked and no issues?
YAY!