Quote:
Originally Posted by wanezhiling
btw, can you tell me the principle of Intel's amazing speed(more than several times the performance of nVidia/AMD)? Thx.
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This is a hard question to be answered in detail and very technical.
Maybe Egur (Eric Gur) at
http://forum.doom9.org/showthread.ph...38#post1523738 can answer this with the help of "inside" Intel information.
First of all Intel's MFX engine (QS) has an obvious advantage over UVDx and VPx.
Greater speed (frequency).
MFX works in the range of 850 MHz - 1100 MHz for most of the desktop processors.
AMD UVD2.2 works at 400MHz ! with no dynamic change of frequency, which means that no matter if you play or benchmark a clip (full load), UVD2.2 always works at 400 MHz
UVD3, VP4 and I'm sure VP5 have dynamic change of working frequency depending on the load.
VP4 reaches 820MHz during benchmarking (full load).
Of course it's not only about frequency, for example because of the integration inside a very fast processor MFX can take advantage of very fast access to memory/ caches.
In general I could say that your question seems of the same principle as of saying why SandyBridge is faster than Bulldozer, or why AMD 79xx series graphics cards (Tahiti architecture) are faster than Nvidia's 5xx series (GF110 architecture)
Of course Sandy, Bulldozer, Southern Island, GF110 architecture chips are extremely complicated chips inside, they are monsters with billions transistors, but executing in the end the same kind of x86 instructions (more or less) for CPU and same kind of D3D, OpenGL, OpenCL instructions for GPUs but with a much different way between different architectures.
Video processors like VP4/5, UVD2.2/3, QuickSync - to be more exact the video decoding/encoding engine of QuickSync is called MFX engine (Multi-Format Codec) - are a lot lot simpler processors than a modern CPU or a GPU processor.
They use fixed function logic, not general purpose logic like CPUs and GPUs (in our days), and they have a form of an ASIC.
They do actually just one thing but they do it extremely fast with very low power consumption, comparing to CPU when you see the low frequency and low number of transistors used by Video processors.
That thing is decoding Video compression algorithms like MPEG-2, MPEG-4 ASP, MPEG-4 AVC, VC-1.
If you study those algorithms you will see that most of the resources needed to decode them are used for Inverse Discrete Cosine Transformations (iDCT) which is a mathematical equation/ transformation.
So if we go deeper, the performance of MFX engine as of every fast video decoder has to do about how quickly performs iDCT, but of course this is a very simple approach of video processor performance.
For example VP5 increased the performance of huge bitrate video clips much more than low bitrate comparing to VP4.
That point has to do with internal changes to access in memory/ caches and wider buses etc.
We need hardware experts and specialized knowledge to go deeper from here, I think!