Affected Models
This problem occurred only on some models of the original Pentium processor. Any Pentium family processor with a clock speed of at least 120 MHz is new enough not to have this bug.
On affected models, the Intel Processor Frequency ID Utility checks for the presence of this bug.
The ten affected processors are listed below. The 39 S-spec of those processors are not listed in the Intel processor specification finder web page.
| Family | Model | Stepping | Core stepping | Clock rate | FSB speed | S-spec |
|---|---|---|---|---|---|---|
| 5 | 1 | 3 | B1 | 60 MHz | 60 MHz | Q0352, Q0412, SX753 |
| 5 | 1 | 3 | B1 | 66 MHz | 66 MHz | Q0353, Q0413, SX754 |
| 5 | 1 | 5 | C1 | 60 MHz | 60 MHz | Q0466, SX835, SZ949 |
| 5 | 1 | 5 | C1 | 66 MHz | 66 MHz | Q0467, SX837, SZ950 |
| Family | Model | Stepping | Core stepping | Clock rate | FSB speed | S-spec |
|---|---|---|---|---|---|---|
| 5 | 2 | 1 | B1 | 75 MHz | 50 MHz | Q0601 |
| 5 | 2 | 1 | B1 | 90 MHz | 60 MHz | Q0542, Q0613, Q0543, SX879, SX885, SX909, SX874 |
| 5 | 2 | 1 | B1 | 100 MHz | 66 MHz | Q0563, Q0587, Q0614, SX886, SX910 |
| 5 | 2 | 2 | B3 | 75 MHz | 50 MHz | Q0606, SX951 |
| 5 | 2 | 2 | B3 | 90 MHz | 60 MHz | Q0628, Q0611, Q0612, SX923, SX922, SX921, SX942, SX943, SX944, SZ951 |
| 5 | 2 | 2 | B3 | 100 MHz | 66 MHz | Q0677, SX960 |
The presence of the bug can be checked manually by performing the following calculation in any application that uses native floating point numbers, including the Windows Calculator or Microsoft Excel in Windows 95/98.
The correct value is
However, the value returned by the flawed Pentium is incorrect beyond four digits:
Another way of detecting the bug is using the pentnt utility included with Windows NT 3.51, Windows NT 4.0, Windows 2000, or Windows XP.
Read more about this topic: Fdiv Bug
Famous quotes containing the words affected and/or models:
“I am less affected by their heroism who stood up for half an hour in the front line at Buena Vista, than by the steady and cheerful valor of the men who inhabit the snow-plow for their winter quarters; who have not merely the three-o’-clock-in-the-morning courage, which Bonaparte thought was the rarest, but whose courage does not go to rest so early, who go to sleep only when the storm sleeps or the sinews of their iron steed are frozen.”
—Henry David Thoreau (1817–1862)
“Grandparents can be role models about areas that may not be significant to young children directly but that can teach them about patience and courage when we are ill, or handicapped by problems of aging. Our attitudes toward retirement, marriage, recreation, even our feelings about death and dying may make much more of an impression than we realize.”
—Eda Le Shan (20th century)