You can run MIDI Guitar standalone: [blog] Clever ways to optimize your plugin usage - #2 by npudar
I’d try first that.
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In the instances way, in the second instance, I’d try with a different driver – FlexASIO or ASIO2WASAPI to see are there any improvements.
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Also, in this particular setup, I wouldn’t go with the buffer of 128, but 64 (if possible).
I personally work with 128, but I use simple setups, there is not much things going around.