Hyperthreading in Core i7 iMac

[Eidorian]

true. each frame of a video requires exactly the same processing (more or less). i wonder if there are even more ways to make video conversions easier/more efficient.

Large cache sizes and the integrated memory controller come more into play here as well.

Frames can be stored in cache or accessed very readily from RAM compared to the front side bus. I do remember talking to Multimedia ages ago on how the 6/12 MB L2 Cache on Penryn/Penryn MCM was the perfect size for storing a 1080p frame. Sadly I don't remember the math right now but the frame storage came under the 6 MB L2 cache size.

 

[DoFoT9]

Large cache sizes and the integrated memory controller come more into play here as well.

Frames can be stored in cache or accessed very readily from RAM compared to the front side bus. I do remember talking to Multimedia ages ago on how the 6/12 MB L2 Cache on Penryn/Penryn MCM was the perfect size for storing a 1080p frame. Sadly I don't remember the math right now but the frame storage came under the 6 MB L2 cache size.

i had a quick look at how to calculate it, but not sure if i am right. from memory you multiply the size of the video by the bitrate.

1920x1080x8 bit colour

=16,588,800bits (per frame)

seems a bit low. even at 24-FPS thats still only 398,131,200bits per second. or roughly 0.3MB/s. maybe im missing something.

working backwards: BD is ~40Mb/s. so 1.66Mb per frame (@24fps). thats a bit closer to the cache size

 

[300D]

I fail to see how a HT enabled CPU will deliver more performance out of an application that is single threaded.

Then you failed to understand what I said.

Let me repeat and emphasize, "HT only works if portions of the CPU core are not being used by another thread and a waiting thread can utilize that unused section. If that unused portion of the CPU cannot execute the thread, or the entire CPU is busy, then HT has zero effect."

 

[MacHamster68]

as long as your operating system and programm cant take full advantage of HT you wont see
a increase in performance , more likely you will see a degrease

 

[300D]

as long as your operating system and programm cant take full advantage of HT you wont see

Then your post doesn't apply to anything involving OSX.