NVIDIA disables PhysX support when ATI GPU is installed

[Dante80]

I would bet good money that there will be few this little tidbit will affect, but NVIDIA has apparently disabled support for PhysX processing on its GPUs when an ATI GPU is present. This would only affect users who have an NVIDIA card installed for PhysX and an ATI card for graphics.


A poster on the NGOHQ forums received an email reply from NVIDIA support explaining the issue. NVIDIA says in part that the issue had to do with some “business reasons” along with quality assurance reasons. This apparently happens with version 186 and newer drivers.

The full email reads:

“Hello JC,

Ill explain why this function was disabled.

Physx is an open software standard any company can freely develop hardware or software that supports it. Nvidia supports GPU accelerated Physx on NVIDIA GPUs while using NVIDIA GPUs for graphics. NVIDIA performs extensive Engineering, Development, and QA work that makes Physx a great experience for customers. For a variety of reasons – some development expense some quality assurance and some business reasons NVIDIA will not support GPU accelerated Physx with NVIDIA GPUs while GPU rendering is happening on non- NVIDIA GPUs. I’m sorry for any inconvenience caused but I hope you can understand.

Best Regards,
Troy
NVIDIA Customer Care”

http://www.slashgear.com/nvidia-disa...alled-2558108/

The main reason I posted this is to ask the following...does that mean that nvidia was assuming hydra is going to work?...

[randomizer]

It took them 2 months to report on this?

[Dante80]

wow...

[Monkeywoman]

WOW, that's just sad on Nvidias part

[RejZoR]

They are signing PhysX death sentence them self. How ridiculous is that? Before at least some existing AMD users bought GeForce for PhysX, but now, they won't. And if they think i'll buy GeForce card just because it has some crappy PhysX, they couldn't be any more wrong. If i'd decide for GeForce, i'd for other reasons. PhysX would be just a cherry on top of all other features. But hey, i guess NVIDIA knows what's doing. Though their PR brilliance from the past looks like a sad desperate attempt to save popularity of their cards where AMD is hammering them from all sides with price and performance.

[Hornet331]

Gg nvidia to piss on your customers.

[Helloworld_98]

it's a legit idea seeing how most people used 9800GT's as PhysX cards and they don't make as much money on those as higher end cards.

[K404]

Better a sale of a 9800GT than no sale at all.

I dont think this is an especially good business decision. nVs determination to keep their features for nVidia-dedicated rigs is not going to work long-term

[Eastcoasthandle]

But wait, there's more. If you act now, you can read what physx can do when a none nvidia card is used.

As I said, enabling the extra PhysX effects on the Radeon cards leads to horrendous performance, like 3-4 FPS, because those effects have to be handled on the CPU. But guess what? I popped Sacred 2 into windowed mode and had a look at Task Manager while the game was running at 3 FPS, and here's what I saw, in miniature:
<pic>
Ok, so it's hard to see, but Task Manager is showing CPU utilization of 14%, which means the game—and Nvidia's purportedly multithreaded PhysX solver—is making use of just over one of our Core i7-965 Extreme's eight front-ends and less than one of its four cores. I'd say that in this situation, failing to make use of the CPU power available amounts to sabotaging performance on your competition's hardware. The truth is that rigid-body physics isn't too terribly hard to do on a modern CPU, even with lots of objects. Nvidia may not wish to port is PhysX solver to the Radeon, even though a GPU like Cypress is more than capable of handling the job. That's a shame, yet one can understand the business reasons. But if Nvidia is going to pay game developers to incorporate PhysX support into their games, it ought to work in good faith to optimize for the various processors available to it. At a very basic level, threading your easily parallelizable CPU-based PhysX solver should be part of that work, in my view.

source

[vietthanhpro]

If it 's true,GT300 will be slower than RV870.

[gOJDO]

They are chopping the branch they sit on...But who cares when there are no PhysX games?

[Final8ty]

Batman Game Play with CPU PhysX all cores trick

Because a Core i7 is more than capable enough of handling PhysX by itself (this is what the tweak does). It allows ALL Cores to be used for PhysX (nVIDIA.. in an attempt to try and claim CPUs can't run PhysX... generally relegate it to a single core). In fact a Core i7 is nearly as powerful (GFLOP wise) in double precision mode as an nVIDIA GT200b Graphics card: http://www.realworldtech.com/page.cf...WT090909050230. A Nehalen Architecture based CPU is capable of around 102GFLOP in single precision (stock) and 55GFLOP is Double Precision while a GT200b based nVIDIA GPU can handle 622-933GFLOP in single precision and 77GFLOP in Double Precision. My understanding of PhysX is that it uses quite a lot of Double Precision calculations (to calculate physical interactions). So on that front they're quite close in performance. This also explains why enablong CPU PhysX (using the tweak) results in all of the PhysX effect while remaining playable.

I'm playing the game with PhysX turned on (since nvIDIA won't allow me to use the 9800GT anymore for dedicated PhysX) and it's entirely playable (I haven't seen it dip bellow 30FPS with ALL the PhysX candy turned on). To prove the point I will upload an HD video on YouTube... keep in mind I am ALSO recording while handling PhysX and the game.. so the CPU is under a lot of pressure yet does it all effortlessly.

http://www.hardforum.com/showpost.ph...06&postcount=8
http://www.youtube.com/watch?v=AUOr4cFWY-s

[>HyperlogiK<]

Are there tweaks for any other games?

[RaZz!]

Batman Game Play with CPU PhysX all cores trick

http://www.hardforum.com/showpost.ph...06&postcount=8
http://www.youtube.com/watch?v=AUOr4cFWY-s

nice find!

i don't have the patience today to follow all these steps, but i think i'll test it with the demo next week for sure

[RejZoR]

That explains why they artificially force PhysX to just 1 core. Because 1 is not enough, but 8 would be perfectly fine. Pathetic.

Btw, what's the trick for enabling this? Or you just enable it in-game and thats it? I've tried Mirror's Edge with and without PhysX on Core i7 and performance was just as ty as it was on my old E5200 @ 3,75GHz.

[billdavis]

hmm someone must be scared

[zalbard]

This's been around for a while and also posted already...
http://www.xtremesystems.org/forums/...d.php?t=231624

[jaredpace]

Btw, what's the trick for enabling this?

http://forums.anandtech.com/messagev...&enterthread=y

[Serra]

Yep, old news, new day.

Normally this thread would be off to the thread graveyard, but I'm just going to lock it now and delete it in a bit because Final8ty's post on enabling all cores of an i7 to use PhysX and getting decent results is probably interesting to some. Feel free to resurrect the old post if you want to comment.