0.9.2 vs. 4.0.1 performance

I have the old one 0.9.2 mitmproxy instance and the new one - 4.0.1

simple performance tests on mitmpdump - https requests on my own server via mitmdump
mitm certificate is not installed, browser chromium with --disable-ssl-false-start --ignore-certificate-errors


4.0.1 is a twice slower

is that possible?

@mhils, any thoughts?