The comment about achievable latency was nothing to do with best practice at gigging, more about the capability of the device. (for live I’ll run as high a buffer that I don’t notice. I can live with 512).
Nothing wrong with a Multiface even in 2019. Driver version is 4.26 from 07/02/2018.
It may be old but it’s rock solid especially at lower latencies for tracking - it beats the (currently produced) BabyFace Pro in that respect. It easily outperforms the vast majority of current USB interfaces with their generic USB chipsets. Regardless of age it’s simply one of the best interfaces in its class. This is why I still use it.
The point is that everything else on the PC works great with it, as one would expect. So the issue is unique to GigPerformer.
I just hope that this issue is a symptom of something that may have an impact elsewhere so is worth fixing, and not just unique to a 15 plus years old soundcard, in which case it may be perceived to be not worth the effort to fix, sadly.
After more testing this issue is linked to GP running on my main DAW only. The Multiface uses a Cardbus adapter running in a Magma Chassis (PCI to PCI bridge, so no drivers in the way here).
When I tried the Cardbus in the laptop using an ExpressCard to Cardbus adapter, the Multiface ran flawlessly down to a buffer of 256 samples.