We have 3 processes that are synchronized with an interprocess mutex. Basically one of them has a multiplier which allows the others to run at a synchronized accelerated rate. Under XP we typically can get it to run at 5000 times realtime. New desktop refreshes are coming out running Windows 7 and the same code with faster machines with more memory are maxing out at 250 times with 95%+ cpu idle time.

Am new to boost so am wondering if we're doing something wrong. Here's the crux of the code. 3 processes and some shared memory. ...

It might be hitting the disk when it shouldn't be. Try pointing SysInternals' ProcMon at each and see if one's doing file accesses where the other isn't. (SysInternals.com.)