Win 10; PT 12.5.2; Processor Affinity
 

Thought I would share my experiences with Win 10 - was on Win 7 with PT 12.4. Downloaded Win 10 'free' upgrade and installed it on a new SSD to get the licence established for my DAW. While the operating system was fresh I decided to test the 12.5.2 update. I also installed Waves Gold Bundle with HEQ, and NI Komplete. I use a MOTU 1248 interface - more details below.

I am pretty happy with the fresh install and everything seems to run great - the 4K monitor support is better in Win 10. However, when I record more complex sessions at low buffer (24bit/96kHz with 128 buffer) I get occasional spikes in CPU activity that cause clicks or CPU errors.

I remembered a thread here at the Avid Forums where someone was adjusting the CPU affinity to reduce the number of cores used by Pro Tools. To test, I adjusted the CPU affinity so that Pro Tools only used 6 of the 8 cores in my i7 3770K. Ta Da. No more pops, the CPU spikes decreased in magnitude, and I was able to run 128 buffer at 24/96 with VIs for recording (see below for more details).

After a quick Google I found a way to set affinity when Pro Tools is being loaded. Google "CPU Affinity Shortcut for a Program - Create in Windows"

For my i7 system with Pro Tools, I have found that leaving 2 cores for the operating system is optimum for best real-time performance - no clicks/pops at 128 buffer.

For example, the command line to start Pro Tools using only 6 of 8 cores for my install:

cmd.e x e /c start "ProTools" /affinity FC "C:\Program Files\Avid\Pro Tools\Protools.exe

<remove spaces in ".exe" above>

I can currently run 24/96 128 buffer while recording/monitoring 12 audio channels and multiple midi-controller-triggered VIs (Kontakt Session Drummer, Piano, EPiano and Horns, and Monarch-Reaktor). With this I get about 5 ms total round trip latency with no pops/clicks or CPU errors.

I will stay on Win 10 for now! My DAW PC never goes online.

Cheers

ejinbc


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Machine Details:
Asus P8Z77 MB, 3770K CPU, 16 GB RAM, 512 GB SSD, 2 TB Data drive, Gigabyte 950 video card running HDMI 2.0 @ 4K resolution, all USB peripherals plugged into USB3 ports EXCEPT Motu 1248 which is plugged into rear USB2 port (no other peripherals plugged into any other USB2 channel - this was necessary to get the latency down without occasional pops in Audio with high midi traffic), Turbo Mode Off in BIOS, C-states Off in BIOS, WiFi Off in BIOS, BT Off in BIOS, On-board sound Off in BIOS, HPET Off in BIOS.

Midi input controllers:
Command 8, Roland TD6, Edirol PCR M80, Korg SP250, Korg Nano

Software:
Windows 10 (all standard DAW optimizations), Pro Tools 12.5.2 - uninstalled App Manager & Web Services, Waves Gold Bundle + Waves HEQ, Native Instruments Komplete 10,

Session details for typical recording:
24 bit, 96 kHz, 12 Audio Tracks, 16 multi-channel Aux VI Tracks, 16 MIDI Tracks, 6 HEQ instances, 1 HDelay instance.

Re: Win 10; PT 12.5.2; Processor Affinity
 

In your command prompt, what does the FC mean, following the word affinity? I did a Google search as you suggested, and I only came upon articles showing how to assign a single core to run a program. For example to use core 0 the command prompt would be to use affinity 1.

Do you really see any benefit from running at 96K? I have done A/B tests over the years and couldn't detect any audible difference between 48K (my normal setting) and anything higher. At 48K, and using 4 of 6 cores for RTAS processing, I sometimes can track at 128 samples, other times I have to bump it up to 256 to avoid the error message that pops up. So if this affinity command would benefit my situation I would like to know more. As you can see from my details below, I am (happily) using a very old PT version on XP, SP3.

Re: Win 10; PT 12.5.2; Processor Affinity
 

FC is a hex code. It equates to 252 in decimal.

Each CPU has a numeric value associated with it. You add up the values for the cores you want to use, then convert to hex.

Decimal to Hex converter: http://www.binaryhexconverter.com/he...imal-converter

Here's an example with 8 cores:

Each core has a decimal value, as follows:

Core 1: 1
Core 2: 2
Core 3: 4
Core 4: 8
Core 5: 16
Core 6: 32
Core 7: 64
Core 8: 128

Let's say you want to use cores 3, 4, 5, 6, 7, and 8.

Add up the values: 4+8+16+32+64+128 = 252

252 in hexadecimal is FC.

That's how he got that value for the command. Because he wanted to use 6 of his 8 available CPUs.

Re: Win 10; PT 12.5.2; Processor Affinity
 

Thanks for the explanation. I think I will try it out on my PT rig. I will use cores 3-6 for PT, so from your explanation: 4+8+16+32 = 60. From the link you gave that converts to a HEX value of 3C. I vaguely recall studying Hexadecimal values in school back in the dark ages, when they actually taught valuable subjects to students.

Re: Win 10; PT 12.5.2; Processor Affinity
 

Sounds right to me!

Re: Win 10; PT 12.5.2; Processor Affinity
 

Unfortunately, it didn't work for me. When I type in the command as shown above and hit enter I get the message: Invalid Switch - "\affinity". Could it be that this command is not supported in Windows XP? When I type "help" in the command promt, it lists various commands, but affinity is not one of them.

Edit: On my Windows 8 Pro computer, typing Help in the command prompt doesn't show affinity as an available choice either. I may check the command-line reference in the online help as it suggested.

Re: Win 10; PT 12.5.2; Processor Affinity
 

Very interesting!
I'll try it.
Thanks.

Enviado de meu SM-G935F usando Tapatalk

Re: Win 10; PT 12.5.2; Processor Affinity
 

/affinity...


Enviado de meu SM-G935F usando Tapatalk

Re: Win 10; PT 12.5.2; Processor Affinity
 

When I did type in the command I had the correct /affinity typed in. But the response the computer gave me it was reported as I showed above. The problem I had was that the command prompt was starting at C:\Documents and Settings\Mike, rather than pointing to the directory where Pro Tools is stored. Even when correcting that, I still couldn't set the affinity using this method. After some research, it may be that the approach may work on XP Professional but not XP Home, which I have.

I set the affinity for Pro Tools manually by going into Task Manager, right clicking on Pro Tools in the Processes Tab and un-clicking 2 of the cores, and then tried to play back a session at a buffer size of 64 samples and then 128 samples and I am still getting the "The operating system held off...try increasing the HW buffer size" message. It is hit or miss with me whether I can run a session with 128 sample buffer size. Some days it works, other days not, even with the same session. CPU usage is quite low as I don't use many virtual instruments or plugins when tracking.