Question Low DPC Latency Graphics Card

bill_phillips

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Aug 22, 2016
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I need to replace my existing DAW (Digital Audio Workstation) graphics card and would like to install one with the lowest driver latency I can afford. According to LatencyMon my existing R7 250 graphics card driver is my highest latency driver at >0.5 ms when I'm using my DAW with the Ethernet port disabled. I have two displays, one each HDMI and VGA. The VGA monitor is flickering so I'm going to replace it with a second HDMI monitor so I'll need a second HDMI interfaces.

Currently audio playback during mixing crackles with ASIO buffers at 1024 samples (the highest sample buffer size available for my 1st gen Focusrite Scarlett 18i8 with 2nd gen drivers) mainly because I use a lot of resource consuming plugins. However, the CPUs 12 threads hardly ever exceed 10% but the graphics card DirectX driver latency is >0.5 ms. In fact the DirectX driver latency never seems to drop below 0.5 ms even now when I'm web browsing. However during browsing the NDIS driver latency is even higher at >2.0 ms.

My video card is in the PCIe 2.0/3.0 x16 slot on my ASUS X99-DELUXE II motherboard which closest to my i7-6850K CPU. My existing graphics card is only x8 but the the slot it's in is x16 and I believe has 16 dedicated PCIe lanes. MY CPU has 40 PCIe lanes. I understand that video performance is not important to DAW performance but driver latency is. So, I'm wondering if using a graphics card that can use all 16 lanes and operate at lower latency would reduce audio crackling during mixing. My motherboard does not have an onboard GPU.

I can't find much about testing graphics cards in DAW applications and all of the benchmarks I've seen are for video processing for various games. DAW graphics performance requirements are low compared to those for gaming. So it would seem that a $100 general computing graphics card would be a good choice, except I have one of those now and it's DPC Latency causes crackling which garbles audio playback during mixing. The question for me is how much do I need to spend to significantly lower DirectX DPC latency? Low noise and power consumption are also important but I'm hoping that won't be a problem because the GPU won't be working very hard.

I've been looking at AMD RX500 series (560-590). I noticed that the 590 at least has a silent mode which would be nice, but it's also the newest and most expensive.

Any suggestions appreciated. Thank you.
 

bill_phillips

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Aug 22, 2016
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Here are System Specs:
CPU: Intel i7-6850K @ 3.60 GHz
Motherboard: ASUS X99-DELUXE II
RAM: Corsair Vengenance LPX 32 GB (4x8GB) 288-Pin DDR4 SDRAM
SSD:
• System Drive: MyDigitalSSD 240GB (256GB) BP5e 80mm SATA III 6G M.2 2280 NGFF SSD (in MB M2 slot)
• Projects Drive: MyDigitalSSD 240GB (256GB) BP5e 80mm SATA III 6G M.2 2280 NGFF SSD (On PCIe board)
• Alt Boot Drive: Samsung SSD 850 EVO 1TB
• Resource Drive: Samsung SSD 850 EVO 250 GB
GPU: ASUS R7250-2GD5 (AMD Radeon R7 250)
PSU: Corsair RM1000i
Chassis: Fractal Define R5
OS: Windows 10 Pro (x64) v1809

I want to improve milti-track audio mixing performance. I don't do any gaming are video editing. I don't need much more than normal desktop graphics capability. What I do need is to reduce the video card DPC latency as much as I can afford to. I don't have a graphics card manufacturer preference. However, my current understanding from anecdotal evidence is that the AMD cards have lower DPC latency times than nVidia cards. And I do want my new graphics card to stay out of the way of my DAW.

My power supply is about 2-years old as is the rest of my computer. I don't expect power consumption or cooling to be a problem because my DAW software doesn't require much in the way of graphics processing. I'm hoping to use the graphics card silent mode if it has one.
 
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Reactions: MikeyMusic
Oct 22, 2019
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Hi Bill, I am in the process of building another DAW PC and was looking into exactly the issue you have highlighted here. Can you tell me how you got on in the end? Cheers Mike
 

bill_phillips

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Aug 22, 2016
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I found out that some of the DAW plugins that I use really drag down CPU performance unless your graphics card has capacity to handle display calculations for those plugins. So I upgraded from a R7 250 to a RX 580 graphics card and BOOM! All of the sudden I could reduce audio buffer size and all 12 of my CPU threads got busy. Now as the mix gets more complex I incrementally increase audio buffer size and CPU utilization drops and drop outs reduce.