But let's keep some realistic context. The audio output is under 1 MBps. You can push that much over original PCI (not express) and ~1ms delay on PCI was "everything must be broken, reset the whole bus". Pushing audio samples both ways on PCIe will not be an issue.

https://www.cycfi.com/2019/04/gpu-dsp-latency/

> PCI-E 3.0 standard guarantees data transfer for 4 kb data with 1-2 μsec (3-10 round trip).

Copying CPU-GPU-CPU:

> size: 8192 bytes, time: 4.72 us,

This should not be a meaningful impact in any audio workflow.