XL2000: Updating Incorrect Calculations on Pentium-Created Worksheet (214003)

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 Calc Now button on the Calculation tab in the Options dialog box, the formulas are not updated with the correct results. (To see the Options dialog box, click Options on the Tools menu.)

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 2000. If you are using a version of Microsoft Excel later than 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, follow these 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.

Select the cell (or cells) on your worksheet that you want to update.
On the Edit menu, click Replace.
In the Find what box, type =. In the Replace with box, type =.

NOTE: Clear the Find entire cells only check box if it is selected.
To recalculate a single cell, click Replace. To recalculate a range of cells, click Replace All.

MORE INFORMATION

The third-party products that are discussed in this article are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, regarding the performance or reliability of these products.

REFERENCES

For additional information about testing for a faulty Pentium FPU, click the article number below to view the article in the Microsoft Knowledge Base:

101467 How to Test for a Faulty Pentium FPU