This article is from the Flight Simulators FAQ, by with numerous contributions by Bob Wittick rwittick@msu.edu others.
Robert Dorsett writes:
Most flight simulators, as with most games, use fixed-point
integer arithmetic. They do this both because most production
machines, until recently, haven't had an FPU, but they also do it
because this approach is significantly *faster* than FPU
performance.
This approach is also used by real-life avionics and simulator
manufacturers, and obviously is not a "limitation." A common
misconception is that an FPU adds more "precision," and leads to
greater "realism." This is wrong.
A simulator must explicitly code for FPU use. Thus, simply by
adding an FPU, one won't see any magical speed changes.
So unless a simulator explicitly *requires* an FPU, or *states*
that it will benefit from an FPU, don't bother buying one, unless
you can use it elsewhere.
Simulators that don't use an FPU:
Hellcats over the Pacific (Mac)
Leyte Gulf (Mac)
ATP (IBM)
FS4 (IBM and Mac)
FS5 (IBM)
Simulators that do:
Elite (all versions, IBM and Mac)
Falcon 3.0 (req'd for High Fidelity model, IBM)
 
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