Windows activity monitor vs. Renoise 3 CPU meter.
I’ve checked the 64 bit version on an i5 processor desktop running 64bit W7, and an old Core2duo PC running 32bit W7, simultaneously, and noticed the meter was correct in the 32 bit version (on the 32bit machine), and the 64 bit version was showing the above screenshot using the 32 bit renoise on the 64bit system.
The 64 bit version of renoise, on the other hand, seems to use a 32 bit bridge for the program itself, reserving 25% of the cpu, (1 of 4 cores seems to be loaded heavier than the rest) Windows system monitor also shows a different CPU percentage here as well.
apologies if this is a known issue already, a search for ‘cpu’ showed nothing in this subforum.