Thread: Real Time CPU
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Old 04-29-2012, 12:06 AM   #33
Nip
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Join Date: Jun 2010
Location: Sweden
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Quote:
Originally Posted by Spectralis View Post
Output device is the USB speaker codec. It doesn't happen as much with other plugins but even then Reaper is not anywhere near utilising all 6 cores and the sound breaks up.

In the SynthMaster example I gave, Reaper is playing just one synth using a lead sound and a monophonic midi file. That's hardly taxing for a USB speaker driver I think.

The problem seems to be that Reaper is unable to utilise all six cores effectively and just maxes out a single core. This seems to be the case because when I set SynthMaster to 'Best' mode the sound breaks up and RTCPU reports 133% CPU utilisation. IOW Reaper is chewing up all of one core because it can't or won't utilise the other 5. Perhaps this is why it glitches.

To put this in context, I regularly edit in Sony Vegas Pro 11 using quite a lot of CPU hungry FX plugins and even when Vegas is utilising nearly all six cores it plays back without glitching. I have to really push it for the sound to break up.
I tested many settings in my i7 and tried firewire for three month:

#1. In BIOS, turn of dynamic overclocking if you got this kind of setting.
#2. In BIOS, turn off core parking.

Both these made cpu go down 20%.

#3. Another thing I learned about HT(HyperThreading) when running on my old daw - a P4 2.8G.

When I ran it as one core only(HT off) I could utilize 65-70% cpu before any crackling occured. When I later changed to HT on(taskmanager shows 2 cores), this started happening at 40-45%.

So lesson learned, the logical cores(HT on) are not same as physical cores.
If running into trouble, I would try and turn off hyperthreading in BIOS.

My i7 shows 8 cores, but it's with HT on.

#4. If running out of cpu and firewire - change to Legacy firewire drivers and cpu will go down about 20% on the core used for audio driver.

#5. Make sure no powersaving options are active on computer. There are setting and profiles that have settings that does not go higher than certain cpu utilization.

See to that you run high performance settings.
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