Basically, the problem is that IB starts processing on one processor, then
something (don't know if it's IB or the operating system) discovers that
the other processor is free, moves the processing over there, discovers
that the other processor now becomes free, moves back - and continues to
move rather than execute the request. I think there is a tool called
IB_Affinity that helps IB use only one processor. This is a problem only in
Windows environments if I remember correctly.

Set

>Could someone tell me why a machine with multiple processors (2 or
>more) would run IB more slowly?
>
>I always thought that multi-processor(MP) support was only a concern
>of the task manager/switcher within the O/S kernel. If the computer
>is running more then 1 thread then it should be able to run half the
>threads on each CPU. You do lose the time the task mananger is
>operating, but that would mean 2 200MHz processors add up to around
>375MHz rather then 400.