On Thor I have a 4KW 24K RPM high speed spindle. The torque curve means that generally at lower RPM there is little grunt.

Ive read about some settings on the VFD where it may be possible to increase the performance, at a cost of heat and/or reliability.

For drilling, going to carbide drills, does this allow me the option to drill at 12K rpm?

For mild steel, most of the speeds and feeds are showing 3K RPM max, of course as I increase the speeds I can do more RPM but there is a point that I cant go faster and I am nowhere near the torque curve. Apart from gearing down, is there any other way to deal with mild steel and a Chinese spindle? Different end mills? Adaptive strategies?

Thanks