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Musings about Cores and Memory and FCP, Oh My.
I’ve had the Activity Monitor up on my second screen for a few days to see
what was happening with CPU and memory usage. I did this initially because
I was setting up Compressor as a virtual cluster and wanted to see if it was
actually using the other cores, which it is. Amazing to watch how fast
Compressor will do an MPEG2 for a DVD now.But the reason for this post is…
I have an 8 core 3 ghz Mac Pro with 8 gigs of memory.
I notice that with FCP, even when rendering, it never uses more than 500%
of the CPU usage, and usually it’s much less. Typically when rendering
it’s from 150 to 400%. When FCP is playing back footage it’s using a
very small amount, like 36%, or not even one complete core.
And as far as memory goes, I have 8 gigs onboard, but FCP only uses
1.36 gigs of real memory but goes out and grabs 2.3 gigs of virtual
memory on the system drive. This can’t help but slow things down.
Virtual memory is SLOW memory.So, I have to wonder a few things here…
Why can’t Apple get FCP to use more of the Cores for rendering?
I see 50% or more idle CPUs when rendering.
And why go out to the hard drive for memory when I’ve got three times
as much real memory just setting there idle.
And, if during playback while FCP is currently using about 36% of a
single core, what would happen if FCP could be using 7 other cores?
Couldn’t we see real time playback of effects?Just wondering?
Thanks,
Dan -
10 Replies
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[Danrnw] “So, I have to wonder a few things here…
Why can’t Apple get FCP to use more of the Cores for rendering?
I see 50% or more idle CPUs when rendering.
And why go out to the hard drive for memory when I’ve got three times
as much real memory just setting there idle.
And, if during playback while FCP is currently using about 36% of a
single core, what would happen if FCP could be using 7 other cores?
Couldn’t we see real time playback of effects?”Supposedly a lot of this is going to change with Leopard. FCP will take better advantage of all the power in the new machines.
Whether this will happen with the updates when Apple releases them or with a full upgrade, say at NAB, is anyone’s guess.
Walter Biscardi, Jr.
Biscardi Creative Media
HD and SD Production for Broadcast and Independent Productions.STOP STARING AND START GRADING WITH APPLE COLOR
The new Color Training DVD now available from the Creative Cow! -
All I can say is that I don’t thin ti’s that easy. While we could see increases in the amount of processing for renders, that’d be nice, I doubt that the processing of real time effects can handed off to the processor, processed and handed back that fast when we have large HD files. This is just a guess. It would be nice to see all the cores crank up when rendering, but again after playing with virtual clusters, they really really work for some things but don’t work for others. It makes me believe that it’s not as easy as just throwing in a few more processors and having everything automatically speed up. Hopefully Leopard will provide some optimization, but I doubt that’s it’ll be the end all be all.
Jeremy
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[Danrnw] “And, if during playback while FCP is currently using about 36% of a
single core, what would happen if FCP could be using 7 other cores?
Couldn’t we see real time playback of effects?”
For playback you only need the cpu that the stream you are playing needs. If you are playing a DV clip, why need your Mac use the 8 cores?
RT playing depends not only of your cpu. Yours HD configuration is very important too. And the capability for RT of FC today is really good, even with smaller computers.
If you have not much real time playback of effects you should have a look to your RT setting.
rafael -
Just an aside, I have the same Mac/RAM as you… Compressor 3 is PAINFULLY slow encoding Mpeg-2. slower than my old G5! I’ve seen a couple other posts of people having problems with Compressor and Mpeg-2 as well.
But encoding in DVDSP with it’s internal encoder is lightning fast.
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Are you using an Apple preset? Are you using 2 pass VBR?
This is what I am saying. There’s no hard and fast rules with Virtual clusters. One thing works great, you change a parameter and everything grinds to a halt.
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Straight up preset: 90 minutes Fast encode.
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Try making your own preset.
It should go faster, at least it did for me.
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[rafalaos] “If you are playing a DV clip, why need your Mac use the 8 cores?”
That’s an excellent point. But if they’re not busy playing my DV clip, maybe some of them can do something useful for me? Like answering my email? Doing my laundry? Fetching my coffee? I mean, they shouldn’t just hang around while that one core’s doing all the work!
Arnie
Now in post: Peristroika, a film by Slava Tsukerman
https://www.arniepix.com/blog -
Yes, tha’s a good idea. i would like some of the lazy cores help me stop smoking:-)
Rafael -
hi all
it makes me wonder too because ive recently come off premier on PC, and my 8 core with 4 gig ram and a comparable graphics card is a little slower than my dual dual core opteron 275 HP9300 with 4 gig ram and no Axio hardware. (both using similar storage and native DV captured files)strange hey?
my guess is it is NOT the system but the FCP software.Mark.
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