Force single CPU

[muzicman0]

I have a dual core system...I have SAC set to force single CPU.

Does it always force SAC to the same CPU core? If so, which on?

I will also be recording using Studio One using my interfaces multi client drivers, which allows me to select which CPU's it uses, and I will move it off of whichever CPU SAC is using.

Thanks for any info!

mm0

[Bob L]

Forcing other programs to a dedicated cpu manually may actually cause more interference... this whole multi cpu interaction thing is not so straightforward... the best you can do is try different configurations and pick the one that works best all around... and in the end... you may find that to be forcing the whole machine to a single cpu.

Bob L

[gdougherty]

Granted I'm running an E8400 and typically showing 30-40% load in SAC, but mixing and recording 32 channels in SAC and Reaper has never caused a problem.

I force single CPU in SAC and let Reaper do what it will.

[muzicman0]

tested yesterday, and it was fine without changing anything. Thanks.

mm0

[JonnyTaylor]

Hi folks,

Still new around here and trying to get my head wrapped around the whole forcing to a single CPU thing. I'm currently only fooling around with SAC on an old Compaq laptop to see if it will suit my needs (and so far so good by the way). If I can get a solid enough feel for the program then I intend to build a new system around it. It'll be a few months till I return to the states so I've got tons of questions and time if you folks have the patience.

So first question...Can someone explain this single CPU thing to me or pass a link to the reasoning. I'm having a hard time finding a definitive answer. It just feels counterintuitive when you can barely find a system with a single core in anything other than a netbook and parts for older systems are getting harder and harder to find.

Thanks

[Bob L]

Nothing to worry about... buy a dual or a quad... in reality testing you can adjust how many cpus are active... many of the multi-core cpus will actually increase clock speed to the active cores when shutting down others.

In realworld testing you may find better or more stable performance with SAC when using less cores due to various issues with the actual bus architecture which can break the pritority threading between the many engine threads. Prority of certain threads over others is what allows the engine to do what it does under load without slipping buffers and glitching the audio stream.

Each system is different and you may find that certain chipsets, video cards, and other things interacting will give you a better performance with less cores than more and stop buffer slipping.

Bob L

[JonnyTaylor]

Very helpful, thank you Mr. Lentini.

My main rig at home in the states is fairly well tweaked to be able to use Presonus StudioLives and do a bit of beta testing for them as well.

I wasn't able to do any real testing with it due mostly to schedule issues with my real job but am very interested in the software as a long term solution to many problems.

Current rig consists of:
Win Vista 64 (Win 7 x 64 eventually but this works well for me ATM),
Gigabyte GA-MA785G-UD3H--Onboard TI Firewire
--AMD Phenom II 965 Quad Core
--8 GB DDR II
--Custom 3U Rackmount
--4 TB Raid (all internal SATA II)
--19" Samsung HDMI LCD on pivoting VESA 1U Mount

With my Presonus gear I've never had a need to minimize the number of cores. I have the throttling disabled and about 300 other OS adjustments.

Do you see any need to look at making any changes to the current system? It is multi-purpose as most of my clientele are corporate and military events requiring multiple video feeds in addition to live sound adn recording in Studio One. I hate to have to shut down cores as I'm worried it will make those capabilities difficult to operate.

[Bob L]

SAC is a different beast than most any other software at the moment... so if you want the best possible performance you will want to setup a system specifically for it.

You should be able to test fine on your setup... but you never know what will cause problems.

First off... Vista would be a no go, in my experience... but for testing, make sure you follow the Win 7 tweaks (in my SAC Support section) about turning OFF the border padding.

Bob L

[JonnyTaylor]

I will do that and thanks. Win 7 will happen eventually but I've got too much cleanup to do at the moment to switch over from Vista.

And I completely understand about never knowing what will cause problems. I normally live in the tech support area over on the Presonus forums. It's scary sommetimes what pops up for questions.

DavidSS1 actually invited me over here when he was having some problems with his FireStudio Lightpipe. And I'm hooked. Just gotta get home to buy this thing. And there will be more questions.

Thanks again.