Serum is slamming real-time peak audio performance meter if track is record enabled

Seriously slamming it - right to the end. Pops, crackles the lot. Not all Serum patches do this, but most seem to. If I manually disable record for the track the problem goes away instantly and completely.

This has just come to my attention, so the project I’m looking at also has some Omnisphere, Keyscape and a Groove Agent tracks. None of these VSTs have this issue, although there is still a noticeable increase in real-time peak when record is enabled for Omnisphere and Keyscape (but not Groove Agent) and the track is selected but it is small, going from virtually nothing to about 1/3 up the bar.

I saw someone suggest this might have to do with enabling the Retrospective Record feature on the Record/MIDI preferences (which it turns out I had enabled at some point to test out or something). Disabling this had a very small effect, not enough to deal with the issue.

So the problem is this:

  1. To be fair Serum seems to be the main culprit here since other instruments don’t appear to slam the peak audio when record is enabled anything like as much but, hey, Serum is popular so a solution to this seems in order.

  2. If I disable enable record on track select in preferences not only does the the ‘*’ on my kb and the record button on my MIDI controller not work to actually record but the sound from the instrument itself is disabled - I have to actually manually click the record enable button on the track list to play the instrument. And then unclick it when I’ve finished playing. No thanks.

So where I’ve got to is that neither disabling record enable on track select nor enabling it are in any way a satisfactory solution.

What other options do I have to deal with this?

Enabling record disables asioguard for that track. So depending on your set latency for your audio card this can have a dramatic effect. Setting buffersize for your audio card 1 or 2 steps higher may cure it for serum.
There can be 2 causes, either these serum patches are very cpu heavy compared to the others or serum is not very optimized for lowest latencies.

Thanks for the suggestion.

I raised my sample rate from 256 to 1024. It did make a difference but sadly only a marginal one.

I can play 4 note chords on most patches without trouble on my new Z390/9900k system, with just one instance of Serum and a 64 sample buffer @ 44.1 kHz.
But yes, Serum is quite CPU heavy, just like U-he Diva and Softube’s Modular… But boy, do they sound good.