CUDA,Physics and Havoc.

[Smn123]

I am considering buying a 5850,I most likely won't eventually but knowledge can't harm, and I could use some advice about my probable choice.Can anyone tell me how nVIDIA's CUDA and physX technologies work(briefly) or at least what's their aim,same counts for ATI's HAVOC.I have to say that I am quite suspicious with fanboys so please justify your opinions as much as possible.Thanks for your time.

[Zero82z]

CUDA is an architecture for running GPGPU applications on GPUs. Basically, it's for general-purpose tasks, not just physics. PhysX is a physics technology that includes support for hardware acceleration through CUDA, meaning it can use CUDA-compatible GPUs to perform physics computations rather than running them on the CPU. Havok is a company that develops physics engines and is now owned by Intel. They were in talks with ATI to develop a framework similar to PhysX for GPU-accelerated physics calculations to be called Havok FX, but once Intel purchased them, those discussions apparently stalled and it seems like the technology is dead in the water right now.

[Fudd Rucker]

Phsyx for gaming is great when you get a title that supports it properly.I think nvidia pulled a douchebag move by gutting hardware physx abilites with ATI gpus present as main display. But there is a work around to get physx to work with an ATI gpu. The only reason im not sporting my usual Nvidia gpu is because the technology has been stagnant for some time. Get your 5850 and be very happy with it lol, if you want cram an 8600GT or a 9600GT in for physx later on.

[kendallcschm]

Physx acceleration can also use the CPU of your computer to process the phisics.. thats what i do.. and cuda allows for using the GPU for compiling and computing of data that normally would use the CPU... its part of whats behind open CL on macs

[belgolas]

Originally Posted by kendallcschm

Physx acceleration can also use the CPU of your computer to process the phisics.. thats what i do.. and cuda allows for using the GPU for compiling and computing of data that normally would use the CPU... its part of whats behind open CL on macs

No cpu on earth can pull off the highest physx games like Batman using the highest physx setting.

I personally have not bought a 5970 partially because it doesn't run physx but I have been close with it in my cart and all I had to do was push that mighty buy me button.

I say get the new gpu or wait for nvidia's 300 series.

[Smn123]

Thanks to all guys,you where helpful.In short,Nvidia's physX will enable the card to perform better,in certain tasks, since it redistributes CPU-GPU roles.Right?Can I run physics with my 8800 GT as a secondary card?And does Nvidia offcially support the,ATI primary-Nvidia for physics,VGA raid so I won't have any problems if I use it?

[Zero82z]

Originally Posted by Smn123

Thanks to all guys,you where helpful.In short,Nvidia's physX will enable the card to perform better,in certain tasks, since it redistributes CPU-GPU roles.Right?

Only in games that use PhysX and support hardware acceleration (right now the list is not very long).

Originally Posted by Smn123

Can I run physics with my 8800 GT as a secondary card?And does Nvidia offcially support the,ATI primary-Nvidia for physics,VGA raid so I won't have any problems if I use it?

1. Yes.

2. nVidia drivers disable PhysX if they detect an ATI card in the system. However, there are workarounds. It is most certainly not officially supported by nVidia though.

[SKYMTL]

Havok will have their Havok Cloth physics calculations which will run on OpenCL. As such, it will be accelerated through NVIDIA and ATI GPUs. Bullet (another physics API) uses OpenCL as well but is being developed on NVIDIA GPUs according to their lead designer. Please remember through, NOT ALL physics calculations should be done on the GPU. Environmental, fluid motion and debris physics need a lot of parallel processing power which the GPU excels at. Meanwhile, ragdoll and rigid body calculations are better done on the CPU.

[Smn123]

So we are talking about a performance premium merely.Given that the game supports PhysX it will be more resourse effective,which means that a better ATI card will run at as well though it will,probably,need more graphics processing power.So since the 5850 is a better a VGA with substantially more computational power than the 275(even the superclocked) it should partly offset the premium 275SO has in Physx supporting games.So PhysX supporting cards don't do sth ATI cards can't,they are just more(maybe seriously more) efficient in some cases.Right or wrong?Shortly,will the 5850 fall behind 275's (Superclocked-Gigabyte) performance seriously,in PhysX supporting games?Is it only a performance lack or is it an image quality lack that is attributed to PhysX properties?

[Zero82z]

Originally Posted by Smn123

So we are talking about a performance premium merely.Given that the game supports PhysX it will be more resourse effective,which means that a better ATI card will run at as well though it will,probably,need more graphics processing power.So since the 5850 is a better a VGA with substantially more computational power than the 275(even the superclocked) it should partly offset the premium 275SO has in Physx supporting games.So PhysX supporting cards don't do sth ATI cards can't,they are just more(maybe seriously more) efficient in some cases.Right or wrong?Shortly,will the 5850 fall behind 275's (Superclocked-Gigabyte) performance seriously,in PhysX supporting games?Is it only a performance lack or is it an image quality lack that is attributed to PhysX properties?

Your understanding is not correct. PhysX performance and graphics performance are not related. Some games that use PhysX introduce extra physics effects that cannot be enabled without a PhysX-supporting card being used. Although a 5850 is faster than a GTX275, it still cannot use these effects whereas a GTX275 can. As for hardware PhysX support providing performance benefits, the issue is that without hardware PhysX, the physics calculations will be performed on the CPU and not the GPU, so the CPU would become the bottleneck in physics-intensive situations. However, that's usually not a major concern.