NVIDIA Responds To GPU PhysX Cheating Allegations

Iria · Jun 25, 2008, 09:29 PM

“During the benchmark install, a runtime library is updated to allow the test to run on the GPU and then during the test, it addresses the benchmark DLLs to the GPU instead of the PPU or CPU. Nothing within the benchmark is changed at all. No software libraries or even a line of code changes in the benchmark whatsoever. The only thing that changes is that installer, nothing else. It has been said that the tests results look different on the screen when running with PhysX enabled on the GPU. And of course this is true, just as the screen results look different when you test on a dual-core CPU versus a quad-core. This isn't a graphics test; it's a physics test. 3DMark Vantage specifically scales more complexity into a scene to take advantage of additional physics compute resources, which of course is why it looks so different/better on a test run with PhysX processing on our GPUs. This is by design in the benchmark and if the folks accusing us took the time to run it, they would know that.”
______________
Source: HotHardware

humonous · Jun 25, 2008, 09:37 PM

from an AMD email sent to press:

"
GPU Physics, PhysX and 3DMark Vantage

We believe physics simulation, whether performed on the CPU or the GPU, will be an increasingly important feature of upcoming games. The powerful parallel processing capabilities of modern GPUs have been proven to be very useful for accelerating some types of physics calculations, such as cloth simulations and rigid body collisions, used to enhance game visuals. However, using the GPU in this way only makes sense if it doesn't detract from graphics rendering performance. In other words, adding a few more moving objects into a scene isn't necessarily beneficial if it requires other 3D effects to be simplified, or sacrifices resolution and frame rate.
3DMark Vantage attempts to address the growing importance of game physics by including support for GPU-accelerated physics in the GPU tests, implemented using DirectX 10 geometry shaders. The developers balanced the physics and rendering workloads in a way they felt was reflective of what we would see in next-generation games. Additionally, they included CPU tests that supported the use of Ageia PhysX PPUs to offload some physics calculations from the CPU. This decision was made prior to the acquisition of Ageia by NVIDIA, and the subsequent discontinuation of discrete PPU products.

Recently released drivers from NVIDIA (ForceWare 177.39) fool the 3DMark Vantage benchmarks into thinking an Ageia PhysX PPU is installed, while actually doing the additional physics processing on the GPU. Since Vantage has separate GPU & CPU benchmarks which both include physics processing, this causes the performance benefits of GPU physics to be double-counted, resulting in an aritificial inflation of the final score. Real games can be expected to limit the amount of GPU physics processing to avoid significantly impacting rendering performance. Also, we are confident that the vast majority of upcoming game titles will not include support for PhysX, but will instead rely on more popular physics middleware (such as Havok) or proprietary physics engines, which will not benefit in any way from NVIDIA 's PhysX drivers.

Note section 3.5 of FutureMark’s 3DMark Vantage Driver approval policy states:

5. Based on the specification and design of the CPU tests, GPU make, type or driver version may not have a significant effect on the results of either of the CPU tests as indicated in Section 7.3 of the 3DMark Vantage specification and whitepaper.”

http://www.futuremark.com/companyinf...y_v100.pdf?m=v

According to FutureMark’s rules NVIDIA drivers that accelerate physics calculations by the GPU will not receive approval and hence are not valid drivers to use for comparison. 3DMark Vantage does have a “Disable PPU” option and utilizing this should more accurately reflect the scores FutureMark intended according to their rules when using NVIDIA ForceWare drivers that accelerate PPU calculations via the GPU under 3DMark Vantage.

We also advise testing boards at the level of ATI Radeon HD 4800 Series in the “High” and “Extreme” modes as these modes place a greater onus on the graphics processing capabilities of the GPU. “Performance” mode settings is more designed for mainstream level GPU’s.
"

Jun 25, 2008, 09:29 PM	#1
Iria DriverHeaven Extreme Member Join Date: Apr 2004 Posts: 7,275 Rep Power: 87	NVIDIA Responds To GPU PhysX Cheating Allegations “During the benchmark install, a runtime library is updated to allow the test to run on the GPU and then during the test, it addresses the benchmark DLLs to the GPU instead of the PPU or CPU. Nothing within the benchmark is changed at all. No software libraries or even a line of code changes in the benchmark whatsoever. The only thing that changes is that installer, nothing else. It has been said that the tests results look different on the screen when running with PhysX enabled on the GPU. And of course this is true, just as the screen results look different when you test on a dual-core CPU versus a quad-core. This isn't a graphics test; it's a physics test. 3DMark Vantage specifically scales more complexity into a scene to take advantage of additional physics compute resources, which of course is why it looks so different/better on a test run with PhysX processing on our GPUs. This is by design in the benchmark and if the folks accusing us took the time to run it, they would know that.” ______________ Source: HotHardware

Jun 25, 2008, 09:37 PM	#2
humonous DriverHeaven Lover Join Date: Jun 2005 Posts: 164 Rep Power: 43	from an AMD email sent to press: " GPU Physics, PhysX and 3DMark Vantage We believe physics simulation, whether performed on the CPU or the GPU, will be an increasingly important feature of upcoming games. The powerful parallel processing capabilities of modern GPUs have been proven to be very useful for accelerating some types of physics calculations, such as cloth simulations and rigid body collisions, used to enhance game visuals. However, using the GPU in this way only makes sense if it doesn't detract from graphics rendering performance. In other words, adding a few more moving objects into a scene isn't necessarily beneficial if it requires other 3D effects to be simplified, or sacrifices resolution and frame rate. 3DMark Vantage attempts to address the growing importance of game physics by including support for GPU-accelerated physics in the GPU tests, implemented using DirectX 10 geometry shaders. The developers balanced the physics and rendering workloads in a way they felt was reflective of what we would see in next-generation games. Additionally, they included CPU tests that supported the use of Ageia PhysX PPUs to offload some physics calculations from the CPU. This decision was made prior to the acquisition of Ageia by NVIDIA, and the subsequent discontinuation of discrete PPU products. Recently released drivers from NVIDIA (ForceWare 177.39) fool the 3DMark Vantage benchmarks into thinking an Ageia PhysX PPU is installed, while actually doing the additional physics processing on the GPU. Since Vantage has separate GPU & CPU benchmarks which both include physics processing, this causes the performance benefits of GPU physics to be double-counted, resulting in an aritificial inflation of the final score. Real games can be expected to limit the amount of GPU physics processing to avoid significantly impacting rendering performance. Also, we are confident that the vast majority of upcoming game titles will not include support for PhysX, but will instead rely on more popular physics middleware (such as Havok) or proprietary physics engines, which will not benefit in any way from NVIDIA 's PhysX drivers. Note section 3.5 of FutureMark’s 3DMark Vantage Driver approval policy states: 5. Based on the specification and design of the CPU tests, GPU make, type or driver version may not have a significant effect on the results of either of the CPU tests as indicated in Section 7.3 of the 3DMark Vantage specification and whitepaper.” http://www.futuremark.com/companyinf...y_v100.pdf?m=v According to FutureMark’s rules NVIDIA drivers that accelerate physics calculations by the GPU will not receive approval and hence are not valid drivers to use for comparison. 3DMark Vantage does have a “Disable PPU” option and utilizing this should more accurately reflect the scores FutureMark intended according to their rules when using NVIDIA ForceWare drivers that accelerate PPU calculations via the GPU under 3DMark Vantage. We also advise testing boards at the level of ATI Radeon HD 4800 Series in the “High” and “Extreme” modes as these modes place a greater onus on the graphics processing capabilities of the GPU. “Performance” mode settings is more designed for mainstream level GPU’s. "