Severe Performance Slowdown When Building Audio Waveforms

I'm experiencing a major performance issue with DaVinci Resolve when working with footage that includes audio, especially when it needs to generate waveforms from files stored on a network server. You can watch my video here of the issue.

Below is a brief summary of the problem and the troubleshooting steps we've taken:

Issue:

When importing footage with audio into DaVinci Resolve, the software struggles to generate audio waveforms, causing extreme system slowdown.

Playback becomes choppy, with significant frame drops, delayed audio, or no audio at all until the waveforms fully build out.

While the footage is on our local 10-gigabit network server, the read/write speed drops dramatically from normal (~800-900MB/s) to as low as 13MB/s during waveform generation.

The performance improves only after leaving Resolve idle for hours, waiting for waveforms to generate.

Temporary Workarounds:

Creating proxies allows audio waveforms to build faster, restoring normal playback and audio responsiveness.
Moving original footage to a local SSD eliminates the problem entirely, with waveforms generating very quickly without network slowdown.

What We Need Help With:

Why is there such a drastic performance drop when building waveforms over a network connection, and is this a known issue?
Are there specific settings or workflows to improve performance when working off a server?
Is this a potential bug in DaVinci Resolve that only occurs when using server-based footage?
We appreciate any advice or solutions to help us avoid these issues without relying on proxies or moving files to a local SSD. Thanks in advance for your help!

Best,
James

Which hardware (CPU, GPU, RAM, disk I/O)? What specific version of Resolve? What OS? What source file codecs? What timeline settings (res and fps)? What framerate? How does your drive rate with Blackmagic Speed Test? How is the drive formatted and connected? Which GPU drivers are installed? What are your cache settings?

Most importantly, have you checked your cache drive location in Project Settings? Project Settings -> Master Settings -> Working Folders. Also, Prefs -> System -> Media Storage. And make sure your Disk Permissions are set correctly.

Somehow it seems that waveform generation in general is quite slow and on 19.0.3 for some files I don't get a waveform at all (nor can synch to those files where waveform generation fails)

When I look at the computer performance, seems the waveform generation uses only the CPU but loads it very, very lightly. Don't have comparative info from earlier versions, but on an AMD CPU (Ryzen 5 5600x) I only see about 5% loads which is (even for single core) very low. So perhaps the waveform generation in general would deserve some code optimization love?

1:Why is there such a drastic performance drop when building waveforms over a network connection, and is this a known issue?
2:Are there specific settings or workflows to improve performance when working off a server?
3:Is this a potential bug in DaVinci Resolve that only occurs when using server-based footage?

I've taken the liberty of slightly adding to your quote for ease of readability.
1: Because the IOPS on a network drive is vastly lower than on a internal computer.
The process on an internal is : Resolve sends a read request -> SDD reads data -> Resolve receives data.
The networked process is: Resolve sends a read request -> the network card converts the request -> the server network card converts request -> SSD reads -> server network card sends data -> network card receives data -> resolve receives data.
It does get exponentially worse if there's HDDs involved, as the latency is orders of magnitude larger. And compounded by reading multiple files at the same time (up to 4 concurrently for davinci 19).

As an example, i created a 1 hour sine wave in AAC in Audacity put it on an internal SSD and a network SSD. Internal finished in 9 seconds, network took 18 seconds.


2: No. The closest thing I can think of is to have the files on a ram drive on the server, but even then it's gonna be slower than an internal SSD.
Even copying the file to an internal SSD, generating the waveform, then relinking, would not help as the pfl file isn't moved automatically. I mean, you could manually copy the pfl file to the new destination (set in Project Settings -> Master Folders (the CacheClip folder)) after relinking to instantly have the waveform (note I have not tested doing that in a live Resolve session, my assumption is that it wouldn't work and that you need to relink, close Resolve, copy file -> start resolve for it to work).

3: No. Davinci will send many read IO requests and networks are not designed for that, they are designed for throughput as you've written).

(Edit: Just measured, with 4 concurrent files read, I average around 18000 IOPS, (4500 IOPS per file))
(Edit 2: I had a bunch of stereo AAC video files to generate waveforms for, I kept rough notes on how long it took with a dc600m SSD (Can not recommend those enough! They are amazing!): 20 hours of timeline waveform generated in 7 wall minutes, 40 hours in 12 minutes, 70 hours in 18 minutes and 90 hours in 24 minutes)
(Edit 3: Change that to 18000 IOPS for 4 files (4500 per file). I used a different less precise program before, now I use System Informer)

To OP

First, thank you for the video.

Can you share what the performance drop, if any, is if you use an SSD external drive on a USB 3 or faster interface instead of network drives?

cheers,
Dorin