Hey Eti Lau,
Thanks for your quick reply!
I will try disabling "use hardware reported latency" as soon as I am able to, hopefully tomorrow, and report back. I have done that though before, with no success, but maybe in combination with the other tweaks it there is a chance this actually would work.
I see what you say about the language barrier, the reply they gave you is not exactly clear...
However, here are my thoughts and experiences so far:
The buffer size can't be changed through Reaper ( block size), only through Tascam Settings panel. However, I don't see this as a problem, only minor inconvenience. I could always change it in the both places, and that would be set and working properly.
I think the problem occurs exactly when CPU or ASIO usage is stressed, i.e. low buffer size, many CPU intensive plugins, loading new plugin or media etc.
When I load a plugin or instrument there would immediately be higher latency that gets introduced in the process. And I'm not talking about the expected latency from the plugin itself, but the base latency with no plugins activated i.e. the latency stays there with no plugins activated. And if I open the preferences window or change the buffer size to something else and than return it to the former setting, the latency goes back to the initial state. So it seems to me that the unit can't auto update the driver after being stressed by the DAW, therefore the driver is most deffinitely the culprit.
And yes, the issue occurs even with only one plugin, so now high load by the software, only momentary spike.
The biggest problem for me really is the latency drifts during recording, because I record a lot of guitars through amp sims, but also VSTi orchestral libraries and oftentimes I need the lowest latency possible. With guitar amp sims I stress the CPU farely quickly, and that often happens in the middle of recording: ASIO spike=latency drifts a bit more. Needless to say, the take gets ruined.
Also because of the drift there is no way to consistently compensate (manually adjust) for the latencies of a given buffer size setting, because they keep changing. I've made many latency loopback tests and every single one pass gives me a different number!
...check to "Listen to this device" in <Listen> tab of property of [US-16x08] from <Recording> tab of (Sound control panel) in Windows sound setting.
This is something I will try too. I have never even seen this setting, so just maybe
it would work...?
As far as other applications, I have tested with Cubase 8/9/10, Sequoia 15 and Reaper 6. No difference. Sequoia even reported lost ASIO buffers on recording, hell, even on playback!
So, you are still in contact with Tascam. By that I assume that you still didn't have the issue resolved?
Thanks and all the best