Regarding the CPU load, there already is a nice trick on the original NTVDM to keep CPU load low, I think most of the people here know it: https://forum.qbasic.at/viewtopic.php?t=2172 Basically, these are TSRs that hook the timer interrupt and release the timeslice to the host CPU on idling. They …

Thanks a lot, leecher, for your proof-of-concept. This also proves that it is possible to implement anything, bypassing the limitations of windows x64. But in my laptop (spec: intel i7-2630qm w/ intel hd3000 integrated videocard, win7x64) NTVDMx64 lags, although the display of console applications …