Luciano Alibrandi, European Product PR Manager for NVIDIA Corporation, has made a correction in regards previous information about NVIDIA’s Unified Compiler and 3DMark03 benchmark after getting into details with the company’s engineers. Apparently, the statement claiming that NVIDIA’s Unified Complier deployed to optimize pixel shader performance is disabled by the new version of 3DMark03 is not fully correct.
“I would like to inform you that a part of my response was not accurate. I stated that the compiler gets disabled, by 3DMark and that is in fact not true,” he said.
So, after all NVIDIA denied the problems between the Unified Compiler technology and the latest version of popular 3DMark03 benchmark. As a result, we may now conclude that the accusations in Futuremark direction from Hans-Wolfram Tismer, a Managing Director for Gainward Europe GmbH were not correct at all.
In October 2003 Santa Clara, California-based NVIDIA Corporation introduced its Unified Compiler integrated in its ForceWare 52.16 drivers to optimize Pixel Shader code for NVIDIA GeForce FX architecture in an attempt to improve performance of graphics cards powered by NVIDIA’s latest GPUs in variety of demanding applications.
NVIDIA said that the Unified Compiler technology tunes DirectX 9.0 execution on the GeForce FX GPUs, and can be used to correct any similar conflict that arises with future APIs. NVIDIA indicated the Unified Compiler as an automatic tuning tool that optimizes Pixel Shader performance in all applications, not just on specific ones. Officials from NVIDIA again stressed today that one of the things the Unified Compiler does is to reinstruct the order of lines of code in a shader. By simply doing this the performance can increase dramatically since the GeForce FX technology is very sensitive to instruction order. So, if the re-ordering is not happening NVIDIA’s GeForce FX parts have a performance penalty.
Since the complier is still active with the new version of 3DMark03 there is currently no explanations for performance drops of certain GeForce FX parts in the latest build 340 of the famous 3DMark03.
“The only change in build 340 is the order of some instructions in the shaders or the registers they use. This means that new shaders are math1ematically equivalent with previous shaders. A GPU compiler should process the old and the new shader code basically with the same performance,” said Tero Sarkkinen, Executive Vice President of Sales and Marketing for Futuremark Corporation – the developer of 3DMark03 application.He was indirectly confirmed by an ATI official yesterday, who said: “ATI has had a compiler since CATALYST 3.6. We did not have any problems with Futuremark’s changes.”