XL:Updating Incorrect Calculations on Pentium-Created Worksheet

ID: Q124310

The information in this article applies to:

SYMPTOMS

When you open a worksheet or workbook in Microsoft Excel, formulas that involve dividing certain combinations of numbers may display unexpected results if the file was created on a computer that contains an Intel Pentium processor. This behavior occurs even if you open the file on a computer that does not contain an Intel Pentium processor, or even after you have installed the Pentium Floating Point Unit (FPU) Patch available from Microsoft.

Additionally, if you press the F9 key or use the calculation buttons on the Calculation tab in the Options dialog box (version 5.0) or in the Calculation Options dialog box (version 4.0), the formulas are not updated with the correct results.

CAUSE

If you are using Microsoft Excel on a computer that contains an Intel Pentium processor, you may receive unexpected results when you perform mathematical operations that involve dividing certain combinations of numbers. This problem is caused by an error in the FPU, a part of the Intel Pentium chip that performs elaborate calculations. Intel is aware of this problem.

If you open a file that contains the incorrect calculations on a computer that does not contain an Intel Pentium processor, or if you have installed the Pentium Floating Point Unit Patch on a computer that contains an Intel Pentium processor, the incorrect calculations are not automatically updated on the worksheet because the formulas have not been changed.

NOTE: The FPU Patch is incorporated into Microsoft Excel 97. If you are using Microsoft Excel 97, it is not necessary to install any type of patch if your computer includes a floating point unit. However, if you open a file saved on another computer, you could still encounter this problem.

WORKAROUND

To update the formulas on your worksheet, either after you have installed the patch, or if you are using a worksheet that was created on a computer with a Pentium processor, you must update the formulas on your worksheet. Use either of the following methods to force the formulas to be recalculated:

Method 1

Force the entire worksheet to be recalculated by pressing CTRL+ALT+F9.

Method 2

Recalculate a single cell or range of cells on your worksheet. To do this, use the following steps:

NOTE: The following method is not recommended if you are using array-type formulas. Replacing the equal sign (=) in these formulas requires you to re-enter any array formulas as arrays.

1. Select the cell (or cells) on your worksheet that you want to update.

2. On the Edit menu, click Replace. (In Microsoft Excel version 4.0, click 

   Replace on the Formula menu.)
3. In the Find What box, type "=" (without the quotation marks). In the 
   Replace With box, type "=" (without the quotation marks). In Microsoft
   Excel version 5.0, clear the Find Entire Cells Only check box if it is
   selected. In Microsoft Excel version 4.0, under Look At, select Part.
4. To recalculate a single cell, click Replace. To recalculate a range of 
   cells, click Replace All.

MORE INFORMATION

For additional information, please see the following article in the Microsoft Knowledge Base: 

   ARTICLE-ID: Q101467
   TITLE     : How to Test for a Faulty Pentium FPU
The Pentium processor is manufactured by Intel, a vendor independent of Microsoft; we make no warranty, implied or otherwise, regarding this product's performance or reliability.

Additional query words: 4.00 4.00a 5.00 5.00c 7.00 7.00a 97 

Keywords          : xlwin 
Version           : WINDOWS:4.0,4.0a,5.0,5.0c,7.0,7.0a,97
Platform          : WINDOWS

Last Reviewed: May 12, 1999