If you use an accelerator card, you may notice that entities such as boxes, circles & Dimensions drawn by hand or using the location bar will not be drawn correctly. For example try to draw the following box with the location bar. (1,-1 by 2,-2) what you will most likely see is a box drawn from .87,-.87 to 1.87,-1.87.
You can turn off SANE Math in most Accelerator cards by selecting the Control panel device and finding the correct check box to turn it off.
If you are using a Prodigy Control Panel device then choose "Off" next to "Sane/881"
You can turn off the SANE portion of the Prodigy CARD by selecting the Prodigy Control panel device and choosing "Off" next to "Sane /881." Unlike the Radius Accelerator you should not restart your machine. If you do you will need to go back into the control panel and turn it off again as the Prodigy board resets SANE when the Macintosh is first turned on.
Note: When you turn Off Sane /881 math will be slower but more accurate.