Inside LiveProfessor there is a gray field labeled something like "DSP use 1%". There has been some confusion among users on what this actually shows and why it does not always show the same as the windows task manager's CPU usage or other such utilities.
The short answer is: They don't show the same thing, don't compare them. They should both stay well bellow 100% for the system to be stable
The technical answer:
Your audio device is set to a buffer size, usually in samples, let's say 256 samples. This is the "chunk" of audio that the audio device gives LiveProfessor to process.
If you are running at a sample rate of 44.1Khz (samples pr second), the audio device calls LiveProfessor and gives it a chunk of 256 samples to process, this happens 172 times pr second (44100 / 256).
This means that LiveProfessor has 5.8 ms to give the audio back to the audio device. (1000/172 or 256/44100*1000) if it takes longer then 5.8 ms to process all the plugins etc, the audio will stutter, or drop out or just crackle, depending on how much longer it takes.
So the DSP meter inside LiveProfessor shows how long it took to process the buffer in relation to the time-frame it is given. so if the buffer is 10 ms and it takes 5 ms to process, it will show 50%
So why does task manager show 10%?
This could be because many VST plugins only run on one core at the time, so the computer as a whole might have 5 CPU cores doing nothing.
LiveProfessor works on all cores, but one plugin only uses one core. so if you have 4 cores and 4 plugins then they (might) all get processed on a separate core.
But, If you have 4 plugins chained, (One going in to the other) then you can't process them at the same time, as they need to wait for each other. These will then be processed on one core, and will take longer.
If you have one plugin routed to 3 others (split) then the 3 last plugins need to wait for the first to finish.
So as you see this can get pretty complex and it all depends on the routing and on the plugins.