Quote:
Originally Posted by TheImperial2004
Come to think of it , How can a GPU processor be 20x faster than CPU ?
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GPUs are VERY highly threaded processors which are fantastic for highly parallelized workload. However they have traditionally been made for processing only graphics data. The recent changes towards GPU programming allows you to do more General Purpose work on them (Hence GP-GPU). CPUs are general purpose processors, and although they can perform a wide variety of work, they are basically a jack of all trade but master of none. For certain tasks which are suitable for GPUs it can outperform CPUs by several orders of magnitude. Notice that "certain tasks", however.
Theoretically a radeon 5970 has 9 times as much double precision floating point calculation ability than the best core i7 980X. Several matrices can be accelerated to be processed more than 9 times faster on such GPUs. However, if the code isn't suitable for such job you can end up actually losing speed compared to a CPU.
As far as I know x264 doesn't use FP calculations and the GPGPU programming landscape is a huge mess right now, so if a port of x264 to GPU would actually bring any advantage to the speed is highly debatable. Then there is the question of optimizing it.