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External sound card to help reducing CPU stress?
saratoga
post Sep 23 2012, 23:02
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QUOTE (slks @ Sep 23 2012, 16:46) *
I'm not familiar with Ableton, but is it possible it's just not very efficient with CPU usage? Or that it stresses that particular chip in a particular way? A bit of Googling has revealed that:

QUOTE
Although marketed as a dual-core processor, the A6-4455M includes only one module with two integer-cores and and floating-point core. As a result, the CPU is not a true dual-core processor.


IIRC effects are done with floating-point mathematics, so it could be that the chip essentially has only 1 core for processing audio.

The site also mentioned the chip has something of a "turbo" mode that bumps up the clock speed by a few hundred mHz. I'm not sure if it's triggered automatically under load, or if it has to be manually set. (My Atom required you to manually activate it with the system tray icon.) Short of getting new hardware, I'd look into that, and also the power-saving settings.


Sharing resources between cores implies a lower peak through put, but not that you somehow only have one core. Separate decode logic will mean that you can very much still benefit from two threads, since its very rare to actually be bottlenecked by FPU on x86. Even if you're working with FP, its very hard to actually saturate all the FPU functional units, so having two cores feeding them will be beneficial.

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washu
post Sep 24 2012, 00:24
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QUOTE (saratoga @ Sep 23 2012, 18:02) *
Sharing resources between cores implies a lower peak through put, but not that you somehow only have one core. Separate decode logic will mean that you can very much still benefit from two threads, since its very rare to actually be bottlenecked by FPU on x86. Even if you're working with FP, its very hard to actually saturate all the FPU functional units, so having two cores feeding them will be beneficial.

By that definition, Hyper-threading is more cores and my i7-2600K is an 8 core CPU. Marketing aside, current AMD Bulldozer/Trinity CPUs have only half the cores they claim to. There is far more shared in each Bulldozer module between the "cores" then just the FPU. It's better than Hyper-threading because less is shared, but it's still not full cores. Being able to run multiple threads (SMT) is not the same thing as true cores (SMP).
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saratoga
post Sep 24 2012, 00:28
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QUOTE (washu @ Sep 23 2012, 19:24) *
By that definition, Hyper-threading is more cores and my i7-2600K is an 8 core CPU.


No, hyperthreading does not duplicate the issue hardware, and so its not analogous.

But more generally, I think the point you're groping for is that counting cores is dumb. What matters is performance and performance per thread. How you get there is irrelevant.

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phofman
post Sep 24 2012, 13:32
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It takes just a single coding blunder to make any DSP hugely inefficient. My bet is the effect is not coded optimally, or the functionality is really computationally demanding.
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Gecko
post Sep 24 2012, 18:16
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What happens when you use the standard audio device instead of Asio4all?
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Katatsumuri
post Sep 25 2012, 00:47
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QUOTE (washu @ Sep 23 2012, 23:44) *
Katatsumuri, try removing (un-installing, not disabling) any and all anti-virus or other "security" software and trying again. It could be trying to scan Ableton's data files when it accesses them and causing the CPU load and disk contention.


I will try that and let you know.

QUOTE (Gecko @ Sep 24 2012, 19:16) *
What happens when you use the standard audio device instead of Asio4all?


I will try that and let you know.

In the meantime I bought a cheap audio interface (TASCAM US-144MKII) and I can say that using dedicated drivers is helping so far. In the most heavy project CPU load percentages are still pretty high when playing all the tracks but around 20% less than I got with asio4all.

About the number-of-cores issue: what about the multicore support button in the settings of ableton? should I turn it off or on? (it's on now)
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washu
post Sep 25 2012, 02:35
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QUOTE (Katatsumuri @ Sep 24 2012, 19:47) *
About the number-of-cores issue: what about the multicore support button in the settings of ableton? should I turn it off or on? (it's on now)

Due to the design of the Bulldozer core there are some rare situations where turning off the second thread in each module improves performance. If I had to guess ableton is not one of those programs, so you should leave it on. However, it doesn't really hurt anything to try. You can also try turning off the multi processing in your BIOS if you have that option.
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Katatsumuri
post Sep 25 2012, 21:40
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Uninstalling the anti-virus software does not help, neither does using standard audio drivers. Disabling multicore support doubles CPU load values and makes it impossible to work (I guess this means that the A6 does work as a dual core unit)
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[JAZ]
post Sep 26 2012, 19:46
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Mmm.. Are you using the same output samplerate on both computers?
Also, in case you're using a higher one, have you tried working at 44Khz on the laptop? (Depending on the effect and its implementation, it can sound different, so be aware of that).

It's clear that you have a CPU limitation, and changing the Khz is what can make the most impact on this.
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Katatsumuri
post Sep 27 2012, 09:25
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I always work at 44khz.

Definitely need OpenCL support by next version of ableton to exploit the real potentiality of this chip.
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