Is physX, done on a single card or do you need to have a  separate card.
Both 
Though some prefer having a dedicated card for physx.
if you have an nvidia graphics card then you only need that for physx and graphics. of course unless your card is really high end you will see performance drops from your card doing both. if you please you can use whatever for graphics and then a 9800 gt is usually a great dedicated physx card.
I'm just weighing decisions, for what i want to do for a graphical update, and this physx shit caught my eye.
so lets say i get http://www.newegg.com/Product/Product.aspx?Item=N82E16814150323 for dedicated physxand http://www.newegg.com/Product/Product.aspx?Item=N82E16814130475 for actual cardOr should i simply gowith ATI HD 5870
what you suggested is often used, gtx 275 with 9800 gt. that sounds good but im an nvidia fan, so if you love physx like me that works great. however if that doesnt mean much to you then you could go with ATI.
you cant go with ATI. physx only works on Nvidia based systems unless you get the fan made patch.
i know, but as i said, if physx doesnt mean much to you. I though with Windows Seven you could run 2 graphics drivers at once, which would allow ATi for graphics and Nvidia for physx if need be. oh well guess i may be wrong.
Well what im asking is will the lesser GPU, be worth having with physx, or should i just flat out go with ATI.
What do you mean by lesser? And physx is amazing and has been ever since Ageia created it so it's definitely worth it.
Edit: I think you mean is having a 9800gt worth it..
Well seeing as how the GTX 275 is already a monster so it'll render physx and graphics just fine. 9800gt will just improve your performance which you probably wouldn't need. So basically no, it's not worth getting for the money.
I think most people that use 8800, 9800gt's for physx is because they upgraded from that card and just decided not to sell it or throw it away and put it to good use.
http://www.legitreviews.com/article/855/1/
That pretty much sums it up. But the 9800gt has a slightly better performance than the 9600gt they used.
ok, my friend has phisx its ok, not that special...
i use ati (2 4890's in crossfire) and its fucking amazing, DX 10 looks amazing... especialy the light rays.
my suggestion is to go with the 5890's
yeah most people just have spare cards. but every once in a while someone buys a 9800 gt for physx.
Yeah, if you have the money to buy it, then go for it. Bragging rights are a must :p
But, if I were you Hopkiller. I would just save up money and wait for the GT300 series.
Look at my other post explaining why ATI fails, imo of course.
yup, im waiting for g300s. im sure the can of whoop ass is coming.
well what im saying is that the HD 5870 out performs the Nvidia 275, in benchmarks. So i was saying should i double up, got with one Nvidia 285. But then i wondered, this is based off benchmarks, is the physX worth it, when the HD 5870 outperforms the GTX 285 as well.
Well put it this way. If you had a GTX 285 in the next few years you will never see a game that it couldn't play (even with physx on). And plus the 285s are $100 cheaper.
It doesn't take a god damn Tesla to process PhysX a ghetto 8600GT will work.
but it depends, maybe paired with a 9800 gtx it will work. but if you have a gtx 285 it can process physx and graphics faster than itself and a 8600.
PhysX is emulated with CUDA.
You can't emulate code faster than 100% It's not even a substantial engine to go out and buy a new card.
That's like buying a sports car then only driving 65mph on a high way.
How will the GTX 360 perform against the HD 5870, and how much is it expected to cost. Because this physx seems cool, and adds a more realistic element to these games.