Hardware choices for maximum performance of effects/filters?

It’s taking a long time to apply some of the filters/effects/plugins in my projects. I often use a second computer and let it process there while I continue to record or edit on my main system. Sometimes I turn the monitor off and leave it in progress overnight. I’ve done all I can on the recording side to reduce the time it takes to run my chains, so at this point it’s a hardware issue. I’ve searched for performance tips, but the only useful page I found was from the Windows ME era.

It’s worth my while to buy or build a new Linux system specifically for audio processing, since this is still cheaper than buying real-time hardware effects (at least, as far as I know… maybe not?), and I prefer to preserve the raw audio anyway, then apply filters and such later in a copy of it.

Anyway, what are the hardware performance bottlenecks for Audacity effects? I realize that there may be two or three different answers to that, depending on the kind of effect.

I use 64-bit Linux, so RAM isn’t much of a limiting factor. All modern CPUs are multi-core, but I don’t know if Audacity and its effects systems and dependencies are multi-threaded. If they aren’t, then I guess I would need a CPU that does single-threaded performance really well. That could be difficult to figure out, since manufacturers haven’t been focusing on single-threaded performance in a long time. Is it possible to use other hardware, like a video card or good sound card to offload some of the processing? I’ve already got a decent SSD, but if I bought 3 more and set up a hardware RAID 0+1 configuration, would that significantly improve performance?

Audacity is mostly a single core, 32-bit application. It may make more use of multiple cores in the future, but that’s dependent on someone doing the development work (which is likely to be a substantial amount of difficult work).

The speed of effects vary tremendously depending on which effect. Nyquist plug-in effects have been particularly slow on Linux, but will benefit from a very substantial increase in speed in the next release (Audacity 2.1.3, which is due for release very soon).

The relatively quick effects (such as “Amplify”) tend to be limited by file i/o and are likely to benefit from faster disk - ideally SSD.
Other effects that do a lot of number crunching, such as Sliding Time Scale / Pitch Shift, are more likely to be limited by processor speed.

Thanks. Unfortunately, that’s what I figured… I haven’t looked into it, but I’m pretty sure that single-threaded performance has not improved in hardware in a long time, and may actually have gotten worse in some cases.

I spent about 3 hours today looking for audio hardware to solve some problems before they even make it to Audacity. These days, most of that is done through software plug-ins that go through ASIO drivers. I kind of hate that idea, it would require new computer hardware anyway, and probably a proprietary DAW as well.

Anyway, I found a rackmount hardware dynamics processor that does fast compression/limiting, pre-amp, de-essing (with phase cancellation), and LMF/MHF EQ control for a little over $600. So I am betting/hoping that a cleaner signal that requires less software post-processing is the time-saving answer I’m looking for. I was under the impression that things like this were several thousand dollars, but I guess I hadn’t considered that it’s a lot cheaper if you look for one with only one or two mono inputs.