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Old 16th April 2018
  #45
Here for the gear
 

Hi

I have reposted this from the Avid Forums to assist others on Windows Systems with low latency...

The Processor Affinity topic comes up every once in a while. I thought I might summarize my efforts for stable low latency performance for people following this thread. So taken from a few earlier posts...

Recent attempts at achieving lower latency while recording a band in PT 2018.1 / Win 10 using a mix of VIs and 12 x 24/96 kHz audio channels. We monitor midi drums (TD6V, Abbey Road Modern Kit), Various Kontakt Keys (2 players), acoustic guitar, and 4 x Vox live through PT during recording. See below for system build details.

With a MOTU 1248 (latest drivers and up-to-date Win 10) I can record without clicks or pops at 24/96 kHz with a 64 sample audio buffer and 32 sample PT output buffer (MOTU allows these to be set separately) for at least 3 hours continuous without issue. Some things that have helped:

1) Use a CPU affinity of ‘FC’ when launching PT ('FFC' for 8700K processors) – this frees up one core for background audio processing on an i7 CPU. This is required on my system to achieve click/pop free operation at low latency – otherwise I get random CPU spikes which will halt recording. At higher buffers (e.g. 256) it is not needed.

This can be achieved on Win 10 with the command line for my install:

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

(note remove space before exe to use these command lines - spaces required to post in forum)

> there are lots of tutorials on setting affinity - for example CPU Affinity Shortcut for a Program - Create in Windows Tutorial | Windows 8 Help Forums

2) Minimize the use of serial processing - recently someone on GS was discussing optimizing your DAW setup to minimize serial processing of audio signals – the more parallel the signal path, the easier it is for the program to schedule across all cores (makes sense). So I route all signals straight to Master Output channels for monitoring. I have one send setup for Vox slapback (HDelay) echo during recording for monitoring.

3) Read the chapter on Groups in PT - Groups can be used for level control to minimize the need for Aux channels (e.g. drums master) – left click to adjust the group (like a VCA), and right click to adjust an individual group members level (wow). I have also started to mix more like this and for many tasks it keeps the mix simpler and easier for me to control. Aux channels can lead to extra serial processing ???


I just built the 8700K system linked below - running Win 10, ProTools 2018.1, MOTU 1248 USB, Waves Gold + HEQ, Kontakt Komplete:

System Builder System Builder - Core i7-8700K 3.7GHz 6-Core, GeForce GTX 950 2GB FTW ACX 2.0, Define R5 (Black) ATX Mid Tower - PCPartPicker Canada - Core i7-8700K 3.7GHz 6-Core, GeForce GTX 950 2GB FTW ACX 2.0, Define R5 (Black) ATX Mid Tower - PCPartPicker Canada

If you want low latency, the 8700K system is probably the way to go because of the faster single core performance.

I overclock to 5.0 GHz. Overclocking is trivial (see YouTube e.g. YouTube) and completely stable on my system. Actually, I find overclocking gives better stability/performance for DAW work. I disable all clock and power switching in the BIOS. I setup a custom fan profile in the BIOS for quieter operation. Airflow is important for overclocking. With the Noctu cooler I reverse the normal case airflow to draw in from the back directly onto the Noctu Radiator, and exhaust out the front. This gets the coolest air over the Radiator for cooling. The CPU never goes above 70C when using ProTools on a busy project.

I am very happy with the 8700K. I had been using an overclocked 3770K (4.5 GHz) for several years waiting for a worthy upgrade. This was it. The single core performance allows me to run at 64 sample buffer 24/96 kHz for recording (16 audio, 16 midi, 6 instances of HEQ, 1 HDelay, 1 Kontakt running AR Modern Drums, 1 Kontakt running Pianos, and then other instances of Kontakt instruments as required), and the 6 cores allow me to run many more CPU intensive plugins during mixing. All good.

I did not delid my CPU; it should not be necessary for 5 GHz. Get the thermal paste right and make sure you have the coolest air possible moving over the radiators. I just used the asus overclock profile for 5 GHz on the Asus Z370 Prime A motherboard and adjusted the XMP for my memory. Once it was working, I lowered the CPU voltage from the overclock default until my system wasn't stable in a stress test then upped the CPU voltage back a few mV. Done stable and cool.

Also note, there is a big difference in CPU load (temperatures) between running a DAW with a busy project and running a Prime stress test. On a stress test the CPU temp cycles from 60 to 85 C, but with a full DAW load it only goes up to 70 C max.

Happy Camper, Hope this helps someone.

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Asus Prime A Z370 MB, 8770K CPU O/C @ 5 GHz, 32 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, Turbo Mode Off in BIOS, C-states Off in BIOS, On-board sound Off in BIOS, HPET Off in BIOS. Command 8, Roland TD6, Edirol PCR M80, Korg SP250. Windows 10 (all standard DAW optimizations), Pro Tools 2018.1, Waves Gold Bundle, Waves HEQ, Native Instruments Komplete 10.