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h.264 encoding on the new MacPro - only 60% CPU usage?!

N

Nik

macrumors 6502a
Original poster
Jun 3, 2007
688
1,492
France
I just received my brand new nehalem MacPro with 8x2.26GHz and noticed that H.264 encoding does not take advantage of all the power the machine provides.
When I use HandBrake to encode a video in h.264 the CPU usage barely hits 60% max.

The same goes for iMovie which only uses about 15% of the CPU when I am exporting a project.

Is there a way to optimize h.264 encoding without buying the Elgato h.264 encoder?!
 
Mine was the same way on the 2.26, and it took a while to do. Then that machine crashed and I just told apple to give me the 2.66Q instead. It uses all the power and got it done 3:26 quicker than the 8 core did.....Im confused too....
 
what version of handbrake are you using. I recently upgraded from 0.9.1 (i think), which used up almost 100% of all 8 cores of my mac pro classic. after upgrading to 0.9.3, I notice that CPU usage hovers around right around 60% of total cpu.
 
I think everyone should wait for the next software for handbrake, it'll make Nehalem 8 core models that much faster.

Plus dont forget 10.5.7. :)
 
3399384767_408db92091.jpg


Only way to get 100% core saturation on 8 core macs.
 
I've noticed on my 2.66 Quad (from 2006) on some encodes the computer will use all of my cores, and on others it will only use 60-70 percent. I have the latest version of the software, too.
 
I'm not a Vikings fan.

try rolling back to version 0.9.1 and check your results. time an encode with 0.9.1 and 0.9.3, and check on cpu usage. h.264 encoding was supposedly optimized in 0.9.3, so even though you may not max cpu usage, that doesn't indicate that it works better/faster than 0.9.3
 
bozz2006 said:
I'm not a Vikings fan.

try rolling back to version 0.9.1 and check your results. time an encode with 0.9.1 and 0.9.3, and check on cpu usage. h.264 encoding was supposedly optimized in 0.9.3, so even though you may not max cpu usage, that doesn't indicate that it works better/faster than 0.9.3
Click to expand...

Could it perhaps be that the optical drive isn't fast enough to saturate all the cores (assuming you guys are ripping from a disc)?
 
Nik said:
I just received my brand new nehalem MacPro with 8x2.26GHz and noticed that H.264 encoding does not take advantage of all the power the machine provides.
When I use HandBrake to encode a video in h.264 the CPU usage barely hits 60% max.

The same goes for iMovie which only uses about 15% of the CPU when I am exporting a project.

Is there a way to optimize h.264 encoding without buying the Elgato h.264 encoder?!
Click to expand...

Usually, my quad core reports 8x100% on CPU usage when transcoding with handbrake. However, occasionally, I will see lower usage with one core at 100%... sorta like the operation in action is only optimized for single processor. I haven't really paid too much attention though...

As for iMovie - I don't think it's optimized for multi cores. I may be wrong about the quicktime exporting, but I think you're not going to see much of an advantage with more cores. Faster clock will make more of a difference in single core action. Right?

-f
 
Has the issue been solved in the meantime?

It somehow annoys me that the saturation is only about 60% when encoding h.264 on my MacPro.
 
The issue is about hyperthreading in the Nehalem machines. Hyperthreading splits the cores so you get 16 on an Octad and 8 on a quad.

Handbrake's latest version is restricted to 8 cores irrespective of hyperthreading or not. So on a Quad Nehalem it will use all 8 virtual cores using the full CPU power. On an Octad it uses 8 hyperthreaded cores with half the capacity.
 
gugucom said:
The issue is about hyperthreading in the Nehalem machines. Hyperthreading splits the cores so you get 16 on an Octad and 8 on a quad.

Handbrake's latest version is restricted to 8 cores irrespective of hyperthreading or not. So on a Quad Nehalem it will use all 8 virtual cores using the full CPU power. On an Octad it uses 8 hyperthreaded cores with half the capacity.
Click to expand...

I don't think this is true because I have an 8-core (so 1600% CPU usage max via Activity Monitor) and Handbrake hovers around 1200-1300% usage when I use it.
 
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