OpenGL 4 FP64 Test: AMD Radeon HD 7970 Surpasses NVIDIA GeForce GTX Titan (*** UPDATED ***)

OpenGL 4 FP64 test - AMD RAdeon vs NVIDIA GeForce


UPDATE (2014.04.15): The scores of the AMD FirePro W9100 are available HERE.


UPDATE (2014.03.06): there is an option in the NVIDIA control panel to enable or disable full speed FP64 support for the GeForce GTX Titan. By default this option is set to OFF. But full speed FP64 support comes with a price: FP32 performance is impacted as it’s described in the NVCPL:

Note that turning on this setting reduces performance for all non-CUDA programs, including games

I updated the GTX Titan scores:
- Julia FP32 score: 71432 points (1189 FPS)
- Julia FP64 score: 31137 points (518 FPS)

When FP64 is enabled, the Julia FP64 score is this time correct and is around 1/3 FP32 (FP32 when FP64 is OFF). But when the FP64 is ON, FP32 performance drops by around 15%.



OpenGL 4 FP64 test - AMD RAdeon vs NVIDIA GeForce



In the freshly released GpuTest 0.7.0 (for Windows, Linux and Mac OS X), we can find a Julia fractal rendered in GLSL using double precision floating point (or FP64) numbers. The Julia FP64 test requires an OpenGL 4 capable GPU and the support of the GL_ARB_gpu_shader_fp64 extension.

The Julia fractal is also available with FP32 (single precision floating point) numbers. That allows some comparisons like the famous ratio between FP32 and FP64 we can read in many reviews(fp64 = 1/xx fp32)…

GpuTest 0.7.0, Julia FP64 test - GeForce GTX Titan
GpuTest 0.7.0, Julia FP64 OpenGL 4.0 test – GeForce GTX Titan



Julia FP32 – Benchmark settings: 1280×720, windowed, MSAA=Off, 60 seconds

106391 points (1771 FPS, Windows, Cat 14.2 beta) – Radeon HD 7970
83324 points (1386 FPS, Windows, R334.89, ***FP64 OFF***) – GeForce GTX Titan
71432 points (1189 FPS, Windows, R334.89, ***FP64 ON***) – GeForce GTX Titan
44105 points (734 FPS, Linux) – Radeon HD 7770
42946 points (715 FPS, Linux, R319.32) – GeForce GTX 680
24293 points (404 FPS, Windows, Cat 14.2 beta) – Radeon HD 6970
23768 points (395 FPS, Windows) – GeForce GTX 750 Ti
6586 points (109 FPS, OSX 10.9) – GeForce GT 650M



Julia FP64 – Benchmark settings: 1280×720, windowed, MSAA=Off, 60 seconds

40885 points (680 FPS, Windows, Cat 14.2 beta) – Radeon HD 7970
31137 points (580 FPS, Windows, R334.89, ***FP64 ON***) – GeForce GTX Titan
12453 points (207 FPS, Windows, Cat 14.2 beta) – Radeon HD 6970
7331 points (122 FPS, Windows, R334.89, ***FP64 OFF***) – GeForce GTX Titan
5037 points (83 FPS, Linux, R319.32) – GeForce GTX 680
4622 points (76 FPS, Linux) – Radeon HD 7770
1872 points (31 FPS, Windows) – GeForce GTX 750 Ti
1041 points (17 FPS, OSX 10.9) – GeForce GT 650M


With current graphics drivers (Catalyst 14.2 beta for AMD Radeon and R319/R334 for NVIDIA), AMD Radeon GPUs are faster than NVIDIA GPUs: in FP32, the Radeon HD 7970 is +27% faster than the GeForce GTX Titan. And the gap is much more important in FP64 where the HD 7970 is 6X faster than the GTX Titan.

If we look at this GFLOPS comparative table, the ratio between FP32 and FP64 is more or less ok for the Radeon HD 7970 (around 1/3 FP32 while the official/marketing ratio is FP64 = 1/4 FP32) but is meaningless for the GTX Titan: the official ratio is FP64 = 1/3 FP32 while in this test, the ratio is rather FP64 = 1/11 FP32. Same thing for the GTX 750 Ti (Maxwell) and for the GTX 680.

In full HD 1920×1080 resolution, the ratio stays the same (FP64 = 1/11 FP32 for the GTX Titan, see HERE and HERE).

Possible causes of this sluggishness in FP64:

  • the GeForce driver (the OpenGL part) is not optimized for this particular use case.
  • there is something wrong in the GLSL code of the Julia fractal that slows down GeForce GPUs. The Julia fractal used in GpuTest is based on this article.
  • GTX Titan FP64 performance is not 1/3 FP32
  • something limits the fp64 performance inside the GeForce driver…
  • other???

MAIN REASON: full speed FP64 is disabled by default on GTX Titan. FP64 can be enabled in NVIDIA control panel.





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