Micro stuttering

Micro stuttering

Micro stuttering is a term used in computing to describe a quality defect inherent to multi-GPU configurations, such as nVidia SLi and AMD CrossFireX, using AFR. It manifests as irregular delays between frames rendered by the multiple GPUs, causing the instantaneous frame rate of the longest delay to be significantly lower than the frame rate reported by benchmarking applications, such as 3DMark, as they usually calculate the average frame rate over a longer time interval. In lower frame rates[note 1] when this effect may be apparent the moving video appears to stutter, resulting in a degraded gameplay experience in the case of a video game, even though the frame rate seems high enough[note 2] to provide a smooth experience. Single-GPU configurations do not suffer from this defect and can in some cases output a subjectively smoother video compared to a multi-GPU setup using the same video card model.[1][2][3][4]

The effects of micro stuttering varies depending on the application and driver optimizations. It remains an issue with both nVidia- and AMD-based multi-card setups as of September 2011, however nVidia's SLI solution is less affected by the phenomenon for dual-GPU setups.[5] Beyond dual-GPU setups, CrossFireX/SLI setups do not seem to be affected by micro-stuttering; the frame rate variability in a three-way CrossFireX setup is just as small as what is achieved by a single GPU.

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See also

Notes

  1. ^ Under which frame rate the effects of micro stuttering becomes apparent varies depending on numerous variables and how sensitive the human test-subject is. The worst-case scenario would be that the frames from all GPUs finish rendering at the same time, in such a case the frame rate perceived by the viewer would be half of the reported average frame rate in the case of a dual-card configuration, and just a fourth in a quad-GPU configuration.
  2. ^ The generally accepted average frame rate for a smooth experience is 40 frame/s or higher.[citation needed]

References

  1. ^ Raffael Vötter (2008-02-08). "Video proof: Micro stuttering may destroy the performance gains from current multi GPU technologies". PC Games Hardware Online. http://www.pcgameshardware.com/aid,631668. Retrieved 2009-11-03. 
  2. ^ Raffael Vötter (2008-07-28). "PCGH proves micro stuttering on the Radeon HD 4870 X2". PC Games Hardware Online. http://www.pcgameshardware.com/aid,653711. Retrieved 2009-11-03. 
  3. ^ Kyle Lunau (2009-05-06). "Micro Stutter: The dark secret of SLI and Crossfire". Overclockers.com. http://www.overclockers.com/micro-stutter-the-dark-secret-of-sli-and-crossfire/. Retrieved 2009-11-03. 
  4. ^ MrWizard6600 (2008-06-20). "GPU Microstuttering FAQ". Hardforum.com. http://hardforum.com/showpost.php?p=1032646751&postcount=1. Retrieved 2010-05-08. 
  5. ^ Igor Wallossek (2011-08-22). "Micro-Stuttering And GPU Scaling In CrossFire and SLI". Tom's Hardware. http://www.tomshardware.com/reviews/radeon-geforce-stutter-crossfire,2995.html. Retrieved 2011-09-24. 

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